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Sample records for deposition ald process

  1. Mechanistic Details of Surface Reactions in Atomic Layer Deposition (ALD) Processes

    Institute of Scientific and Technical Information of China (English)

    Menno; Bouman; Christopher; Clark; Hugo; Tiznado; Francisco; Zaera

    2007-01-01

    1 Results The reaction mechanisms of the atomic layer deposition (ALD) processes used for thin-film growth have been characterized by a combination of surface sensitive techniques. Our early studies focused on the deposition of TiN films from TiCl4 and ammonia,starting with the independent characterization of each of the two half steps comprising the ALD process. It was found that exposure of the substrate to TiCl4 leads to the initial deposition of titanium in the +3 oxidation state; only at a later st...

  2. Unearthing [3-(Dimethylamino)propyl]aluminium(III) Complexes as Novel Atomic Layer Deposition (ALD) Precursors for Al2 O3 : Synthesis, Characterization and ALD Process Development.

    Science.gov (United States)

    Mai, Lukas; Gebhard, Maximilian; de Los Arcos, Teresa; Giner, Ignacio; Mitschker, Felix; Winter, Manuela; Parala, Harish; Awakowicz, Peter; Grundmeier, Guido; Devi, Anjana

    2017-08-10

    Identification and synthesis of intramolecularly donor-stabilized aluminium(III) complexes, which contain a 3-(dimethylamino)propyl (DMP) ligand, as novel atomic layer deposition (ALD) precursors has enabled the development of new and promising ALD processes for Al2 O3 thin films at low temperatures. Key for this promising outcome is the nature of the ligand combination that leads to heteroleptic Al complexes encompassing optimal volatility, thermal stability and reactivity. The first ever example of the application of this family of Al precursors for ALD is reported here. The process shows typical ALD like growth characteristics yielding homogeneous, smooth and high purity Al2 O3 thin films that are comparable to Al2 O3 layers grown by well-established, but highly pyrophoric, trimethylaluminium (TMA)-based ALD processes. This is a significant development based on the fact that these compounds are non-pyrophoric in nature and therefore should be considered as an alternative to the industrial TMA-based Al2 O3 ALD process used in many technological fields of application. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Density functional theory study on the full ALD process of silicon nitride thin film deposition via BDEAS or BTBAS and NH3.

    Science.gov (United States)

    Huang, Liang; Han, Bo; Han, Bing; Derecskei-Kovacs, Agnes; Xiao, Manchao; Lei, Xinjian; O'Neill, Mark L; Pearlstein, Ronald M; Chandra, Haripin; Cheng, Hansong

    2014-09-14

    A detailed reaction mechanism has been proposed for the full ALD cycle of Si3N4 deposition on the β-Si3N4(0001) surface using bis(diethylamino)silane (BDEAS) or bis(tertiarybutylamino)silane (BTBAS) as a Si precursor with NH3 acting as the nitrogen source. Potential energy landscapes were derived for all elementary steps in the proposed reaction network using a periodic slab surface model in the density functional approximation. Although the dissociative reactivity of BTBAS was slightly better than that of BDEAS, the thermal deposition process was still found to be an inherently high temperature process due to the high activation energies during the dissociative chemisorption of both precursors and the surface re-amination steps. These results underline the need to develop new precursors and alternative nitrogen sources when low temperature thermal silicon nitride films are targeted.

  4. Atomic layer deposition (ALD): A versatile technique for plasmonics and nanobiotechnology.

    Science.gov (United States)

    Im, Hyungsoon; Wittenberg, Nathan J; Lindquist, Nathan C; Oh, Sang-Hyun

    2012-02-28

    While atomic layer deposition (ALD) has been used for many years as an industrial manufacturing method for microprocessors and displays, this versatile technique is finding increased use in the emerging fields of plasmonics and nanobiotechnology. In particular, ALD coatings can modify metallic surfaces to tune their optical and plasmonic properties, to protect them against unwanted oxidation and contamination, or to create biocompatible surfaces. Furthermore, ALD is unique among thin-film deposition techniques in its ability to meet the processing demands for engineering nanoplasmonic devices, offering conformal deposition of dense and ultra-thin films on high-aspect-ratio nanostructures at temperatures below 100 °C. In this review, we present key features of ALD and describe how it could benefit future applications in plasmonics, nanosciences, and biotechnology.

  5. Processing of n+/p-/p+ strip detectors with atomic layer deposition (ALD) grown Al2O3 field insulator on magnetic Czochralski silicon (MCz-si) substrates

    Science.gov (United States)

    Härkönen, J.; Tuovinen, E.; Luukka, P.; Gädda, A.; Mäenpää, T.; Tuominen, E.; Arsenovich, T.; Junkes, A.; Wu, X.; Li, Z.

    2016-08-01

    Detectors manufactured on p-type silicon material are known to have significant advantages in very harsh radiation environment over n-type detectors, traditionally used in High Energy Physics experiments for particle tracking. In p-type (n+ segmentation on p substrate) position-sensitive strip detectors, however, the fixed oxide charge in the silicon dioxide is positive and, thus, causes electron accumulation at the Si/SiO2 interface. As a result, unless appropriate interstrip isolation is applied, the n-type strips are short-circuited. Widely adopted methods to terminate surface electron accumulation are segmented p-stop or p-spray field implantations. A different approach to overcome the near-surface electron accumulation at the interface of silicon dioxide and p-type silicon is to deposit a thin film field insulator with negative oxide charge. We have processed silicon strip detectors on p-type Magnetic Czochralski silicon (MCz-Si) substrates with aluminum oxide (Al2O3) thin film insulator, grown with Atomic Layer Deposition (ALD) method. The electrical characterization by current-voltage and capacitance-voltage measurement shows reliable performance of the aluminum oxide. The final proof of concept was obtained at the test beam with 200 GeV/c muons. For the non-irradiated detector the charge collection efficiency (CCE) was nearly 100% with a signal-to-noise ratio (S/N) of about 40, whereas for the 2×1015 neq/cm2 proton irradiated detector the CCE was 35%, when the sensor was biased at 500 V. These results are comparable with the results from p-type detectors with the p-spray and p-stop interstrip isolation techniques. In addition, interestingly, when the aluminum oxide was irradiated with Co-60 gamma-rays, an accumulation of negative fixed oxide charge in the oxide was observed.

  6. Dynamic Modeling for the Design and Cyclic Operation of an Atomic Layer Deposition (ALD Reactor

    Directory of Open Access Journals (Sweden)

    Curtisha D. Travis

    2013-08-01

    Full Text Available A laboratory-scale atomic layer deposition (ALD reactor system model is derived for alumina deposition using trimethylaluminum and water as precursors. Model components describing the precursor thermophysical properties, reactor-scale gas-phase dynamics and surface reaction kinetics derived from absolute reaction rate theory are integrated to simulate the complete reactor system. Limit-cycle solutions defining continuous cyclic ALD reactor operation are computed with a fixed point algorithm based on collocation discretization in time, resulting in an unambiguous definition of film growth-per-cycle (gpc. A key finding of this study is that unintended chemical vapor deposition conditions can mask regions of operation that would otherwise correspond to ideal saturating ALD operation. The use of the simulator for assisting in process design decisions is presented.

  7. Processing of n{sup +}/p{sup −}/p{sup +} strip detectors with atomic layer deposition (ALD) grown Al{sub 2}O{sub 3} field insulator on magnetic Czochralski silicon (MCz-si) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Härkönen, J., E-mail: jaakko.harkonen@helsinki.fi [Helsinki Institute of Physics (Finland); Tuovinen, E. [Helsinki Institute of Physics (Finland); VTT Technical Research Centre of Finland, Microsystems and Nanoelectronics (Finland); Luukka, P.; Gädda, A.; Mäenpää, T.; Tuominen, E.; Arsenovich, T. [Helsinki Institute of Physics (Finland); Junkes, A. [Institute for Experimental Physics, University of Hamburg (Germany); Wu, X. [VTT Technical Research Centre of Finland, Microsystems and Nanoelectronics (Finland); Picosun Oy, Tietotie 3, FI-02150 Espoo Finland (Finland); Li, Z. [School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan 411105 (China)

    2016-08-21

    Detectors manufactured on p-type silicon material are known to have significant advantages in very harsh radiation environment over n-type detectors, traditionally used in High Energy Physics experiments for particle tracking. In p-type (n{sup +} segmentation on p substrate) position-sensitive strip detectors, however, the fixed oxide charge in the silicon dioxide is positive and, thus, causes electron accumulation at the Si/SiO{sub 2} interface. As a result, unless appropriate interstrip isolation is applied, the n-type strips are short-circuited. Widely adopted methods to terminate surface electron accumulation are segmented p-stop or p-spray field implantations. A different approach to overcome the near-surface electron accumulation at the interface of silicon dioxide and p-type silicon is to deposit a thin film field insulator with negative oxide charge. We have processed silicon strip detectors on p-type Magnetic Czochralski silicon (MCz-Si) substrates with aluminum oxide (Al{sub 2}O{sub 3}) thin film insulator, grown with Atomic Layer Deposition (ALD) method. The electrical characterization by current–voltage and capacitance−voltage measurement shows reliable performance of the aluminum oxide. The final proof of concept was obtained at the test beam with 200 GeV/c muons. For the non-irradiated detector the charge collection efficiency (CCE) was nearly 100% with a signal-to-noise ratio (S/N) of about 40, whereas for the 2×10{sup 15} n{sub eq}/cm{sup 2} proton irradiated detector the CCE was 35%, when the sensor was biased at 500 V. These results are comparable with the results from p-type detectors with the p-spray and p-stop interstrip isolation techniques. In addition, interestingly, when the aluminum oxide was irradiated with Co-60 gamma-rays, an accumulation of negative fixed oxide charge in the oxide was observed.

  8. Atomic layer deposition (ALD) as a coating tool for reinforcing fibers.

    Science.gov (United States)

    Roy, A K; Baumann, W; König, I; Baumann, G; Schulze, S; Hietschold, M; Mäder, T; Nestler, D J; Wielage, B; Goedel, W A

    2010-03-01

    Layers of alumina were deposited on to bundled carbon fibers in an atomic layer deposition (ALD) process via sequential exposure to vapors of aluminium chloride and water, respectively. Scanning electron microscopic (SEM) images of the coated fibers revealed that each individual fiber within a bundle was coated evenly and separately, fibers are not bridged by the coating. SEM and transmission electron microscopic (TEM) images indicate that the coating was uniform and conformal with good adhesion to the fiber surface. Average deposition rate, measured from SEM images, was 0.06 nm per cycle at 500 °C. SEM also revealed that at deposition temperatures of 500 °C few of the fibers were damaged. At temperatures of 300 °C, no damaged fibers were observed, the average deposition rate decreased down to 0.033 nm per cycle. Oxidation resistance of the alumina-coated fibers was characterized by thermogravimetric analysis (TGA). The alumina coating improved oxidation resistance of the carbon fiber significantly. Oxidation onset temperature was 600 °C for fibers coated with a 45 nm thick alumina. Uncoated fibers, on the other hand, started to oxidize at temperatures as low as 250 °C.

  9. Formation of PbTe nanofilms by electrochemical atomic layer deposition (ALD)

    Energy Technology Data Exchange (ETDEWEB)

    Banga, Dhego O.; Vaidyanathan, Raman; Xuehai, Liang [Department of Chemistry, University of Georgia, Athens, GA 30602-2556 (United States); Stickney, John L. [Department of Chemistry, University of Georgia, Athens, GA 30602-2556 (United States)], E-mail: Stickney@chem.uga.edu; Cox, Stephen; Happeck, Uwe [Department of Physics and Astronomy, University of Georgia, Athens, GA 30602-2556 (United States)

    2008-10-01

    This article describes optimization of a cycle for the deposition of lead telluride (PbTe) nanofilms using electrochemical atomic layer deposition (ALD). PbTe is of interest for the formation of thermoelectric device structures. Deposits were formed using an ALD cycle on Au substrates, one atomic layer at a time, from separate solutions, containing Pb{sup 2+} or HTeO{sub 2}{sup +} ions. Single atomic layers were formed using surface limited reactions, referred to as underpotential deposition (UPD), so the deposition cycle consisted of alternating UPD of Te and Pb. The Pb deposition potential was maintained at -0.35 V throughout the 100 cycle-runs, while the Te deposition potential was ramped up from -0.55 V to -0.40 V over the first 20 cycles and then held constant for the remaining ALD cycles. Coulometry for the reduction of both Te and Pb indicated coverages near one monolayer, each cycle. Electron probe microanalysis (EPMA) indicated a uniform and stoichiometric deposit, with a Te/Pb ratio of 1.01. X-ray diffraction measurement showed that the thin films had the rock salt structure, with a preferential (2 0 0) orientation for the as formed deposits. No annealing was used. Infrared reflection absorption measurements of PbTe films formed with 50, 65, and 100 cycles indicated strong quantum confinement.

  10. Atomic layer deposition for semiconductors

    CERN Document Server

    Hwang, Cheol Seong

    2014-01-01

    This edited volume discusses atomic layer deposition (ALD) for all modern semiconductor devices, moving from the basic chemistry of ALD and modeling of ALD processes to sections on ALD for memories, logic devices, and machines.

  11. Preparation and characterization of ALD deposited ZnO thin films studied for gas sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boyadjiev, S.I., E-mail: boiajiev@gmail.com [MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria); Georgieva, V. [Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria); Yordanov, R. [Department of Microelectronics, Technical University of Sofia, 8 Kliment Ohridski Blvd., 1756 Sofia (Bulgaria); Raicheva, Z. [Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria); Szilágyi, I.M. [MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, Szent Gellért tér 4, Budapest, H-1111 (Hungary)

    2016-11-30

    Highlights: • For the first time the gas sensing towards NO{sub 2} of very thin ALD ZnO films is studied. • The very thin ALD ZnO films showed excellent sensitivity to NO{sub 2} at room temperature. • These very thin film ZnO-based QCM sensors very well register even low concentrations. • The sensors have fully reversible sorption and are able to be recovered in short time. • Described fast and cost-effective ALD deposition of ZnO thin films for QCM gas sensor. - Abstract: Applying atomic layer deposition (ALD), very thin zinc oxide (ZnO) films were deposited on quartz resonators, and their gas sensing properties were studied using the quartz crystal microbalance (QCM) method. The gas sensing of the ZnO films to NO{sub 2} was tested in the concentration interval between 10 and 5000 ppm. On the basis of registered frequency change of the QCM, for each concentration the sorbed mass was calculated. Further characterization of the films was carried out by various techniques, i.e. by SEM-EDS, XRD, ellipsometry, and FTIR spectroscopy. Although being very thin, the films were gas sensitive to NO{sub 2} already at room temperature and could register very well as low concentrations as 100 ppm, while the sorption was fully reversible. Our results for very thin ALD ZnO films show that the described fast, simple and cost-effective technology could be implemented for producing gas sensors working at room temperature and being capable to detect in real time low concentrations of NO{sub 2}.

  12. Hot-wire assisted ALD: from idea to realization

    NARCIS (Netherlands)

    Kovalgin, Alexey

    2016-01-01

    Atomic Layer Deposition (ALD) was conventionally developed as a purely thermal process to deposit two-element films such as oxides and nitrides. ALD of single-element films (metals and semiconductors), with a few exceptions, is still a difficult task. Plasma-enhanced ALD (PEALD) can enable depositio

  13. Atomic Layer Deposition (ALD) grown thin films for ultra-fine pitch pixel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Härkönen, J. [Helsinki Institute of Physics, CMS Upgrade Project, Helsinki (Finland); Ott, J. [Helsinki Institute of Physics, CMS Upgrade Project, Helsinki (Finland); Laboratory of Radio Chemistry, University of Helsinki (Finland); Mäkelä, M. [Laboratory of Inorganic Chemistry, University of Helsinki (Finland); Arsenovich, T.; Gädda, A.; Peltola, T. [Helsinki Institute of Physics, CMS Upgrade Project, Helsinki (Finland); Tuovinen, E. [Helsinki Institute of Physics, CMS Upgrade Project, Helsinki (Finland); VTT Technical Research Centre of Finland, Microsystem and Nanoelectronics (Finland); Luukka, P.; Tuominen, E. [Helsinki Institute of Physics, CMS Upgrade Project, Helsinki (Finland); Junkes, A. [Institute for Experimental Physics, University of Hamburg (Germany); Niinistö, J.; Ritala, M. [Laboratory of Inorganic Chemistry, University of Helsinki (Finland)

    2016-09-21

    In this report we cover two special applications of Atomic Layer Deposition (ALD) thin films to solve these challenges of the very small size pixel detectors. First, we propose to passivate the p-type pixel detector with ALD grown Al{sub 2}O{sub 3} field insulator with a negative oxide charge instead of using the commonly adopted p-stop or p-spray technologies with SiO{sub 2}, and second, to use plasma-enhanced ALD grown titanium nitride (TiN) bias resistors instead of the punch through biasing structures. Surface passivation properties of Al{sub 2}O{sub 3} field insulator was studied by Photoconductive Decay (PCD) method and our results indicate that after appropriate annealing Al{sub 2}O{sub 3} provides equally low effective surface recombination velocity as thermally oxidized Si/SiO{sub 2} interface. Furthermore, with properly designed annealing steps, the TiN thin film resistors can be tuned to have up to several MΩ resistances with a few µm of physical size required in ultra-fine pitch pixel detectors.

  14. Atomic Layer Deposition (ALD) grown thin films for ultra-fine pitch pixel detectors

    Science.gov (United States)

    Härkönen, J.; Ott, J.; Mäkelä, M.; Arsenovich, T.; Gädda, A.; Peltola, T.; Tuovinen, E.; Luukka, P.; Tuominen, E.; Junkes, A.; Niinistö, J.; Ritala, M.

    2016-09-01

    In this report we cover two special applications of Atomic Layer Deposition (ALD) thin films to solve these challenges of the very small size pixel detectors. First, we propose to passivate the p-type pixel detector with ALD grown Al2O3 field insulator with a negative oxide charge instead of using the commonly adopted p-stop or p-spray technologies with SiO2, and second, to use plasma-enhanced ALD grown titanium nitride (TiN) bias resistors instead of the punch through biasing structures. Surface passivation properties of Al2O3 field insulator was studied by Photoconductive Decay (PCD) method and our results indicate that after appropriate annealing Al2O3 provides equally low effective surface recombination velocity as thermally oxidized Si/SiO2 interface. Furthermore, with properly designed annealing steps, the TiN thin film resistors can be tuned to have up to several MΩ resistances with a few μm of physical size required in ultra-fine pitch pixel detectors.

  15. Refractive index sensitivity enhancement of optical fiber cladding mode by depositing nanofilm via ALD technology.

    Science.gov (United States)

    Zhao, Ying; Pang, Fufei; Dong, Yanhua; Wen, Jianxiang; Chen, Zhenyi; Wang, Tingyun

    2013-11-04

    The atomic layer deposition (ALD) technology is introduced to enhance the sensitivity of optical fiber cladding mode to surrounding refractive index (SRI) variation. The highly uniform Al2O nanofilm was deposited around the double cladding fiber (DCF) which presents cladding mode resonant feature. With the high refractive index coating, the cladding mode resonant spectrum was tuned. And the sensitivity enhancement for SRI sensor was demonstrated. Through adjusting the deposition cycles, a maximum sensitivity of 723 nm/RIU was demonstrated in the DCF with 2500 deposition cycles at the SRI of 1.34. Based on the analysis of cladding modes reorganization, the cladding modes transition of the coated DCF was investigated theoretically. With the high performance nanofilm coating, the proposed SRI sensor is expected to have wide applications in chemical sensors and biosensors.

  16. Crystalline silicon surface passivation by thermal ALD deposited Al doped ZnO thin films

    Directory of Open Access Journals (Sweden)

    Jagannath Panigrahi

    2017-03-01

    Full Text Available The evidence of good quality silicon surface passivation using thermal ALD deposited Al doped zinc oxide (AZO thin films is demonstrated. AZO films are prepared by introducing aluminium precursor in between zinc and oxygen precursors during the deposition. The formation of AZO is confirmed by ellipsometry, XRD and Hall measurements. Effective minority carrier lifetime (τeff greater than 1.5ms at intermediate bulk injection levels is realized for symmetrically passivated p-type silicon surfaces under optimised annealing conditions of temperature and time in hydrogen ambient. The best results are realised at 450°C annealing for >15min. Such a layer may lead to implied open circuit voltage gain of 80mV.

  17. Formation of palladium nanofilms using electrochemical atomic layer deposition (E-ALD) with chloride complexation.

    Science.gov (United States)

    Sheridan, Leah B; Gebregziabiher, Daniel K; Stickney, John L; Robinson, David B

    2013-02-05

    Pd thin films were formed by electrochemical atomic layer deposition (E-ALD) using surface-limited redox replacement (SLRR) of Cu underpotential deposits (UPD) on polycrystalline Au substrates. An automated electrochemical flow deposition system was used to deposit Pd atomic layers using a sequence of steps referred to as a cycle. The initial step was Cu UPD, followed by its exchange for Pd ions at open circuit, and finishing with a blank rinse to complete the cycle. Deposits were formed with up to 75 cycles and displayed proportional deposit thicknesses. Previous reports by this group indicated excess Pd deposition at the flow cell ingress, from electron probe microanalysis (EPMA). Those results suggested that the SLRR mechanism did not involve direct transfer between a Cu(UPD) atom and a Pd(2+) ion that would take its position. Instead, it was proposed that electrons are transferred through the metallic surface to reduce Pd(2+) ions near the surface where their activity is highest. It was proposed that if the cell was filled completely before a significant fraction of the Cu(UPD) atoms had been oxidized then the deposit would be homogeneous. Previous work with EDTA indicated that the hypothesis had merit, but it proved to be very sensitive to the EDTA concentration. In the present study, chloride was used to complex Pd(2+) ions, forming PdCl(4)(2-), to slow the exchange rate. Both complexing agents led to a decrease in the rate of replacement, producing more homogeneous films. Although the use of EDTA improved the homogeneity, it also decreased the deposit thickness by a factor of 3 compared to the thickness obtained via the use of chloride.

  18. Identification of optimal ALD process conditions of Nd{sub 2}O{sub 3} on Si by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Xiaojiao; Liu, Hongxia; Zhang, Xujie [Xidian University, School of Microelectronics, Key Laboratory of Wide Band Gap Semiconductor Materials and Devices, Xi' an (China)

    2014-02-15

    Variable angle spectroscopic ellipsometry (VASE) is used to investigate the thickness and optical properties of Nd{sub 2}O{sub 3} films deposited by atomic layer deposition (ALD) at various process conditions. It is found that the films exhibit good thickness uniformity and an almost constant growth rate of 0.42 aa/cycle in the temperature region of 290-330 C. Further examination of the imaginary part of the dielectric functions of the selected samples demonstrates that all optically observable dielectric-related defects are located in the interface layer between the silicon substrate and the native oxide rather than in the bulk Nd{sub 2}O{sub 3} layer. And, the defects within the band gap of the interface are found to be strongly affected by the deposition temperature. In the deposition temperature range of 300-320 C, only one absorption peak of 3.53 eV besides the silicon substrate's critical features is observed, indicating that the Si/SiO{sub 2}/Nd{sub 2}O{sub 3} stacks contain the fewest interfacial defects. Then the optimal ALD process condition for Nd{sub 2}O{sub 3} is determined as Nd(thd){sub 3} (thd = 2,2,6,6,-tetramethyl-3,5-heptanedionato) evaporation temperature: 185 C, deposition temperature: 300-320 C, saturation condition: Nd(thd){sub 3} and pulse time longer than 0.5 s. (orig.)

  19. A growth model for the HfO{sub 2} ALD process

    Energy Technology Data Exchange (ETDEWEB)

    Michling, Marcel; Tallarida, Massimo; Kolanek, Krzysztof; Schmeisser, Dieter [Brandenburgische Technische Universitaet Cottbus, Angewandte Physik/Sensorik, K.-Wachsmann-Allee 1, 03046 Cottbus (Germany)

    2011-07-01

    In this contribution we report on our in-situ{sup 2} cycle-by-cycle (up to the 25 cycles) investigation of the HfO{sub 2} atomic layer deposition (ALD) process using the method of x-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS). We used Tetrakis-Dimethyl-Amino-Hafnium (TDMA-Hf) and H{sub 2}O as precursors and p-type Si wafer with native oxide as a substrate. The XPS measurements were carried out at BESSY II in Berlin with primary energies of 150 eV and 640 eV and the EELS measurements were done with a primary energy of 50 eV. We measured the O 1s, Si 2p core level and the valence band including the Hf 4f core level. From the H f4f to Si 2p ratios taken at each energy we developed a growth model for the first monolayer and for the following layers too. From our data we conclude, that in the first monolayer up to the fourth ALD cycle an island growth occurs. The height of these islands is about 0.5 nm. After the first monolayer is completed, a layer- by-layer growth can be expected. In order to proof this observation we have simulated the Hf/Si ratio for different excitation energies and found a very good agreement with our measurement data. The EELS data especially the evaluation of the loss function onset confirm our growth model.

  20. High Throughput Atomic Layer Deposition Processes: High Pressure Operations, New Reactor Designs, and Novel Metal Processing

    Science.gov (United States)

    Mousa, MoatazBellah Mahmoud

    Atomic Layer Deposition (ALD) is a vapor phase nano-coating process that deposits very uniform and conformal thin film materials with sub-angstrom level thickness control on various substrates. These unique properties made ALD a platform technology for numerous products and applications. However, most of these applications are limited to the lab scale due to the low process throughput relative to the other deposition techniques, which hinders its industrial adoption. In addition to the low throughput, the process development for certain applications usually faces other obstacles, such as: a required new processing mode (e.g., batch vs continuous) or process conditions (e.g., low temperature), absence of an appropriate reactor design for a specific substrate and sometimes the lack of a suitable chemistry. This dissertation studies different aspects of ALD process development for prospect applications in the semiconductor, textiles, and battery industries, as well as novel organic-inorganic hybrid materials. The investigation of a high pressure, low temperature ALD process for metal oxides deposition using multiple process chemistry revealed the vital importance of the gas velocity over the substrate to achieve fast depositions at these challenging processing conditions. Also in this work, two unique high throughput ALD reactor designs are reported. The first is a continuous roll-to-roll ALD reactor for ultra-fast coatings on porous, flexible substrates with very high surface area. While the second reactor is an ALD delivery head that allows for in loco ALD coatings that can be executed under ambient conditions (even outdoors) on large surfaces while still maintaining very high deposition rates. As a proof of concept, part of a parked automobile window was coated using the ALD delivery head. Another process development shown herein is the improvement achieved in the selective synthesis of organic-inorganic materials using an ALD based process called sequential vapor

  1. MOCVD and ALD of rare earth containing multifunctional materials. From precursor chemistry to thin film deposition and applications

    Energy Technology Data Exchange (ETDEWEB)

    Milanov, Andrian Petrov

    2010-03-26

    The present thesis deals with the development of metal-organic complexes of rare elements. They should be used as novel precursors for the production of rare earth thin films by metal-organic chemical vapor deposition (MOCVD) and Atomic Layer Deposition (ALD). Within the work two precursor classes were examined, the tris-Malonato-complexes as well as the tris-Guanidinato-complexes of a series of rare earth metals. The latter showed excellent properties regarding to their volatility, their thermal stability, the defined decomposition and high reactivity towards water. They have been successfully used as precursors for the MOCVD of rare earth oxide layers. By using of a gadolinium guanidinate it could also be shown that the rare earth guanidinates are promising precursors for ALD of rare earth oxide and MOCVD of rare earth nitride layers. [German] Die vorliegende Dissertation beschaeftigt sich mit der Entwicklung von metallorganischen Komplexen der Seltenerd-Elemente. Diese sollten als neuartigen Precursoren fuer die Erzeugung von seltenerdhaltigen Duennschichten mittels Metallorganischer Chemischer Dampfabscheidung (MOCVD) und Atomic Layer Deposition (ALD) eingesetzt werden. Innerhalb der Arbeit wurden zwei Precursorklassen untersucht, die Tris-Malonato-Komplexe sowie die Tris-Gunanidinato-Komplexe einer Reihe von Seltenerdmetallen. Letztere zeigten hervorragende Eigenschaften bezueglich ihrer Fluechtigkeit, ihrer thermischen Stabilitaet, der definierten Zersetzung und der hohen Reaktivitaet gegenueber Wasser. Sie wurden erfolgreich als Precursoren fuer die MOCVD von Seltenerd-Oxid-Schichten eingesetzt. Unter Verwendung eines Gadolinium Guanidinats konnte ausserdem gezeigt werden, dass die Seltenerd-Guanidinate vielversprechende Precursoren fuer die ALD von Seltenerd-Oxid-Schichten sowie die MOCVD von Seltenerd-Nitrid-Schichten darstellen.

  2. Prevention of Ultraviolet (UV)-Induced Surface Damage and Cytotoxicity of Polyethersulfone Using Atomic Layer Deposition (ALD) Titanium Dioxide

    Science.gov (United States)

    Petrochenko, Peter E.; Scarel, Giovanna; Hyde, G. Kevin; Parsons, Gregory N.; Skoog, Shelby A.; Zhang, Qin; Goering, Peter L.; Narayan, Roger J.

    2013-04-01

    Nanostructured surfaces are finding use in several medical applications, including tissue scaffolds and wound dressings. These surfaces are frequently manufactured from biocompatible polymers that are susceptible to ultraviolet (UV) damage. Polyethersulfone (PES) is a biocompatible polymer that undergoes oxidation and degradation when exposed to ultraviolet (UV) light. A uniform TiO2 coating can protect PES during exposure to UV sources (e.g., germicidal lamps and sunlight). The goal of this study was to determine whether atomic layer deposition (ALD) can successfully be used to grow TiO2 onto PES, protect it from UV irradiation, and reduce macrophage in vitro cytotoxicity. TiO2 was ALD-coated onto PES at 21 nm thickness. Uncoated PES exposed to UV for 30 min visibly changed color, whereas TiO2-coated PES showed no color change, indicating limited degradation. Macrophages exposed to UV-treated PES for 48 h showed reduced cell viability (via MTT assay) to 18% of control. In contrast, the cell viability for UV-treated TiO2-coated PES was 90% of control. Non-UV treated PES showed no decrease in cell viability. The results indicate that ALD of TiO2 thin films is a useful technique to protect polymers from UV damage and to retain low cytotoxicity to macrophages and other types of cells that are involved in wound healing. TiO2- coated PES membranes also have potential use in direct methanol fuel cells and in wastewater treatment membranes.

  3. Formation of Micro- and Nanostructures on the Nanotitanium Surface by Chemical Etching and Deposition of Titania Films by Atomic Layer Deposition (ALD

    Directory of Open Access Journals (Sweden)

    Denis V. Nazarov

    2015-12-01

    Full Text Available In this study, an integrated approach was used for the preparation of a nanotitanium-based bioactive material. The integrated approach included three methods: severe plastic deformation (SPD, chemical etching and atomic layer deposition (ALD. For the first time, it was experimentally shown that the nature of the etching medium (acidic or basic Piranha solutions and the etching time have a significant qualitative impact on the nanotitanium surface structure both at the nano- and microscale. The etched samples were coated with crystalline biocompatible TiO2 films with a thickness of 20 nm by Atomic Layer Deposition (ALD. Comparative study of the adhesive and spreading properties of human osteoblasts MG-63 has demonstrated that presence of nano- and microscale structures and crystalline titanium oxide on the surface of nanotitanium improve bioactive properties of the material.

  4. Influence of deposition temperature of thermal ALD deposited Al2O3 films on silicon surface passivation

    Science.gov (United States)

    Batra, Neha; Gope, Jhuma; Vandana, Panigrahi, Jagannath; Singh, Rajbir; Singh, P. K.

    2015-06-01

    The effect of deposition temperature (Tdep) and subsequent annealing time (tanl) of atomic layer deposited aluminum oxide (Al2O3) films on silicon surface passivation (in terms of surface recombination velocity, SRV) is investigated. The pristine samples (as-deposited) show presence of positive fixed charges, QF. The interface defect density (Dit) decreases with increase in Tdep which further decreases with tanl up to 100s. An effective surface passivation (SRV<8 cm/s) is realized for Tdep ≥ 200 °C. The present investigation suggests that low thermal budget processing provides the same quality of passivation as realized by high thermal budget process (tanl between 10 to 30 min).

  5. ~3-nm ZnO Nanoislands Deposition and Application in Charge Trapping Memory Grown by Single ALD Step

    Science.gov (United States)

    El-Atab, Nazek; Chowdhury, Farsad; Ulusoy, Turkan Gamze; Ghobadi, Amir; Nazirzadeh, Amin; Okyay, Ali K.; Nayfeh, Ammar

    2016-12-01

    Low-dimensional semiconductor nanostructures are of great interest in high performance electronic and photonic devices. ZnO is considered to be a multifunctional material due to its unique properties with potential in various applications. In this work, 3-nm ZnO nanoislands are deposited by Atomic Layer Deposition (ALD) and the electronic properties are characterized by UV-Vis-NIR Spectrophotometer and X-ray Photoelectron Spectroscopy. The results show that the nanostructures show quantum confinement effects in 1D. Moreover, Metal-Oxide-Semiconductor Capacitor (MOSCAP) charge trapping memory devices with ZnO nanoislands charge storage layer are fabricated by a single ALD step and their performances are analyzed. The devices showed a large memory window at low operating voltages with excellent retention and endurance characteristics due to the additional oxygen vacancies in the nanoislands and the deep barrier for the trapped holes due to the reduction in ZnO electron affinity. The results show that the ZnO nanoislands are promising in future low power memory applications.

  6. Modeling Mechanism and Growth Reactions for New Nanofabrication Processes by Atomic Layer Deposition.

    Science.gov (United States)

    Elliott, Simon D; Dey, Gangotri; Maimaiti, Yasheng; Ablat, Hayrensa; Filatova, Ekaterina A; Fomengia, Glen N

    2016-07-01

    Recent progress in the simulation of the chemistry of atomic layer deposition (ALD) is presented for technologically important materials such as alumina, silica, and copper metal. Self-limiting chemisorption of precursors onto substrates is studied using density functional theory so as to determine reaction pathways and aid process development. The main challenges for the future of ALD modeling are outlined.

  7. Processing Polynomial Algebraic Problems by Using SAC—2/ALDES

    Institute of Scientific and Technical Information of China (English)

    刘卓军

    1991-01-01

    This paper discusses the portability of SAC-2/ALDES and reviews some applications in polynomial algebra.Furthermore,we indicate that the concept of the safety variable in the SAC-2/ALDES is not proper.When,for example,we used safety variable in isolating complex roots of polynomials,something wrong happened.

  8. Influence of purge, time of waiting and TiCl4 dosing time in a low-pressure atomic layer deposition (ALD reactor on properties of TiO2 layer

    Directory of Open Access Journals (Sweden)

    W. Walke

    2017-01-01

    Full Text Available The aim of the study was to evaluate the influence of the ALD process parameters on mechanical properties and corrosion resistance of TiO2 layer. The TiO2 layer was deposited on stainless steel surfaces at constant temperature T = 200 °C and number of cycles nc = 500 (g ≈ 25 nm. The applied methodology consisted of potentiodynamic and impedance studies, as well as adhesion test. The obtained results were the basis for selection of surface treatment method for stainless steel implants for contact with blood. Appropriate parameters of surface treatment realized by means of the ALD method is of significant importance. It will contribute to the development of technological conditions of specified deposition parameters of TiO2 layers on steel implants.

  9. Impact of ALD Coating on Mn-rich Cathode Materials (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Santhanagopalan, S.

    2013-06-01

    LG Chem Power Inc. (LGCPI) and NREL have collaborated to demonstrate the scalability of the atomic layer deposition (ALD) coating process over the last 6 months, and the benefits of ALD coatings for long-term cycling and calendar life are being quantified. The objectives of this work are two-fold: 1) to evaluate the scalability of the process to coat LGCPI cathodes with alumina using the ALD technique, and 2) to demonstrate improvements in rate capability and life of ALD-coated LGCPI electrodes. NREL received samples of baseline material to be coated from LGCPI. NREL carried out ALD coating of the samples with help from a subcontractor, ALD Nanosolutions. NREL fabricated cells from those samples for quick screening and feedback to ALD Nanosolutions. LGCPI is currently fabricating larger-format cells for further evaluation.

  10. Sensor-based atomic layer deposition for rapid process learning and enhanced manufacturability

    Science.gov (United States)

    Lei, Wei

    In the search for sensor based atomic layer deposition (ALD) process to accelerate process learning and enhance manufacturability, we have explored new reactor designs and applied in-situ process sensing to W and HfO 2 ALD processes. A novel wafer scale ALD reactor, which features fast gas switching, good process sensing compatibility and significant similarity to the real manufacturing environment, is constructed. The reactor has a unique movable reactor cap design that allows two possible operation modes: (1) steady-state flow with alternating gas species; or (2) fill-and-pump-out cycling of each gas, accelerating the pump-out by lifting the cap to employ the large chamber volume as ballast. Downstream quadrupole mass spectrometry (QMS) sampling is applied for in-situ process sensing of tungsten ALD process. The QMS reveals essential surface reaction dynamics through real-time signals associated with byproduct generation as well as precursor introduction and depletion for each ALD half cycle, which are then used for process learning and optimization. More subtle interactions such as imperfect surface saturation and reactant dose interaction are also directly observed by QMS, indicating that ALD process is more complicated than the suggested layer-by-layer growth. By integrating in real-time the byproduct QMS signals over each exposure and plotting it against process cycle number, the deposition kinetics on the wafer is directly measured. For continuous ALD runs, the total integrated byproduct QMS signal in each ALD run is also linear to ALD film thickness, and therefore can be used for ALD film thickness metrology. The in-situ process sensing is also applied to HfO2 ALD process that is carried out in a furnace type ALD reactor. Precursor dose end-point control is applied to precisely control the precursor dose in each half cycle. Multiple process sensors, including quartz crystal microbalance (QCM) and QMS are used to provide real time process information. The

  11. Classification of processes for the atomic layer deposition of metals based on mechanistic information from density functional theory calculations

    Science.gov (United States)

    Elliott, S. D.; Dey, G.; Maimaiti, Y.

    2017-02-01

    Reaction cycles for the atomic layer deposition (ALD) of metals are presented, based on the incomplete data that exist about their chemical mechanisms, particularly from density functional theory (DFT) calculations. ALD requires self-limiting adsorption of each precursor, which results from exhaustion of adsorbates from previous ALD pulses and possibly from inactivation of the substrate through adsorption itself. Where the latter reaction does not take place, an "abbreviated cycle" still gives self-limiting ALD, but at a much reduced rate of deposition. Here, for example, ALD growth rates are estimated for abbreviated cycles in H2-based ALD of metals. A wide variety of other processes for the ALD of metals are also outlined and then classified according to which a reagent supplies electrons for reduction of the metal. Detailed results on computing the mechanism of copper ALD by transmetallation are summarized and shown to be consistent with experimental growth rates. Potential routes to the ALD of other transition metals by using complexes of non-innocent diazadienyl ligands as metal sources are also evaluated using DFT.

  12. Classification of processes for the atomic layer deposition of metals based on mechanistic information from density functional theory calculations.

    Science.gov (United States)

    Elliott, S D; Dey, G; Maimaiti, Y

    2017-02-07

    Reaction cycles for the atomic layer deposition (ALD) of metals are presented, based on the incomplete data that exist about their chemical mechanisms, particularly from density functional theory (DFT) calculations. ALD requires self-limiting adsorption of each precursor, which results from exhaustion of adsorbates from previous ALD pulses and possibly from inactivation of the substrate through adsorption itself. Where the latter reaction does not take place, an "abbreviated cycle" still gives self-limiting ALD, but at a much reduced rate of deposition. Here, for example, ALD growth rates are estimated for abbreviated cycles in H2-based ALD of metals. A wide variety of other processes for the ALD of metals are also outlined and then classified according to which a reagent supplies electrons for reduction of the metal. Detailed results on computing the mechanism of copper ALD by transmetallation are summarized and shown to be consistent with experimental growth rates. Potential routes to the ALD of other transition metals by using complexes of non-innocent diazadienyl ligands as metal sources are also evaluated using DFT.

  13. Spatial atomic layer deposition: a route towards further industrialization of atomic layer deposition

    NARCIS (Netherlands)

    Poodt, P.W.G.; Cameron, D.C.; Dickey, E.; George, S.M.; Kuznetsov, V.; Parsons, G.N.; Roozeboom, F.; Sundaram, G.; Vermeer, A.

    2012-01-01

    Atomic layer deposition (ALD) is a technique capable of producing ultrathin conformal films with atomic level control over thickness. A major drawback of ALD is its low deposition rate, making ALD less attractive for applications that require high throughput processing. An approach to overcome this

  14. Selective Ru ALD as a Catalyst for Sub-Seven-Nanometer Bottom-Up Metal Interconnects.

    Science.gov (United States)

    Zyulkov, Ivan; Krishtab, Mikhail; De Gendt, Stefan; Armini, Silvia

    2017-09-13

    Integrating bottom-up area-selective building-blocks in microelectronics has a disruptive potential because of the unique capability of engineering new structures and architectures. Atomic layer deposition (ALD) is an enabling technology, yet understanding the surfaces and their modification is crucial to leverage area-selective ALD (AS-ALD) in this field. The understanding of general selectivity mechanisms and the compatibility of plasma surface modifications with existing materials and processes, both at research and production scale, will greatly facilitate AS-ALD integration in microelectronics. The use of self-assembled monolayers to inhibit the nucleation and growth of ALD films is still scarcely compatible with nanofabrication because of defectivity and downscaling limitations. Alternatively, in this Research Article, we demonstrate a straightforward H2 plasma surface modification process capable of inhibiting Ru ALD nucleation on an amorphous carbon surface while still allowing instantaneous nucleation and linear growth on Si-containing materials. Furthermore, we demonstrate how AS-ALD enables previously inaccessible routes, such as bottom-up electroless metal deposition in a dual damascene etch-damage free low-k replacement scheme. Specifically, our approach offers a general strategy for scalable ultrafine 3D nanostructures without the burden of subtractive metal patterning and high cost chemical mechanical planarization processes.

  15. Effect of process parameters on surface morphology and characterization of PE-ALD SnO{sub 2} thin films for gas sensing

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Gwangpyo [JAMIC, Sunchun, Jeonnam 540-856 (Korea, Republic of); Satyanarayana, L. [Research Institute of Energy Resources Technology, Chosun University, Gwangju 501-759 (Korea, Republic of); Park, Jinseong [Department of Advanced Materials Engineering, Chosun University, Gwangju 501-759 (Korea, Republic of)]. E-mail: jsepark@chosun.ac.kr

    2006-09-15

    Tin dioxide (SnO{sub 2}) thin films were deposited by plasma enhanced-atomic layer deposition (PE-ALD) on Si(1 0 0) substrate using dibutyl tin diacetate (DBTA) ((CH{sub 3}CO{sub 2}){sub 2}Sn[(CH{sub 2}){sub 3}-CH{sub 3}]{sub 2}) as precursor. The process parameters were optimized as a function of substrate temperature, source temperature and purging time. It is observed that the surface phenomenon of the thin films was changed with film thickness. Atomic force microscopy (AFM) images and X-ray diffraction (XRD) pattern were used to observe the texture and crystallanity of the films. The films deposited for 100, 200 and 400 cycles were characterized by XPS to determine the chemical bonding properties. XPS results reveal that the surface dominant oxygen species for 100, 200 and 400 cycles deposited films are O{sub 2} {sup -}, O{sup -} and O{sup 2-}, respectively. The 200 cycles film has exhibited highest concentration of oxygen (O{sup -}) species before and after annealing. Conductivity studies revel that this film has best adsorption strength to the oxygen ions forming on the surface. The sensor with 200 cycles SnO{sub 2} thin film has shown highest sensitivity to CO gas than other films. A correlation between the characteristics of Sn3d{sub 5/2} and O1s XPS spectra before and after annealing and the electrical behavior of the SnO{sub 2} thin films is established.

  16. Comparison of ALD and IBS Al2O3 films for high power lasers

    Science.gov (United States)

    Liu, Hao; Jensen, Lars; Becker, Jürgen; Wurz, Marc Christopher; Ma, Ping; Ristau, Detlev

    2016-12-01

    Atomic layer deposition (ALD) has been widely studied in Micro-electronics due to its self-terminating property. ALD also grows film coatings with precise thickness and nodular-free structure, which are desirable properties for high power coatings. The depositing process was studied to produce uniform, stable and economic Al2O3 single layers. The layer properties relevant to high power laser industry were studied and compared with IBS Al2O3 single layers. ALD Al2O3 showed a stable growth of 0.104 nm/cycle, band gap energy of 6.5 eV and tensile stress of about 480 MPa. It also showed a low absorption at wavelength 1064 nm within several ppm, and LIDT above 30 J/cm2. These properties are superior to the reference IBS Al2O3 single layers and indicate a high versatility of ALD Al2O3 for high power coatings.

  17. Deposition of conductive TiN shells on SiO2 nanoparticles with a fluidized bed ALD reactor

    NARCIS (Netherlands)

    Didden, A.; Hillebrand, P.; Wollgarten, M.; Dam, B.; Van de Krol, R.

    2016-01-01

    Conductive TiN shells have been deposited on SiO2 nanoparticles (10–20 nm primary particle size) with fluidized bed atomic layer deposition using TDMAT and NH3 as precursors. Analysis of the powders confirms that shell growth saturates at approximately 0.4 nm/cycle at TDMAT doses of >1.2 mmol/g of p

  18. Effect of Atomic Layer Depositions (ALD)-Deposited Titanium Oxide (TiO2) Thickness on the Performance of Zr40Cu35Al15Ni10 (ZCAN)/TiO2/Indium (In)-Based Resistive Random Access Memory (RRAM) Structures

    Science.gov (United States)

    2015-08-01

    ARL-TR-7399 ● AUG 2015 US Army Research Laboratory Effect of Atomic Layer Depositions (ALD)- Deposited Titanium Oxide (TiO2...Thickness on the Performance of Zr40Cu35Al15Ni10 (ZCAN)/ TiO2/Indium (In)-Based Resistive Random Access Memory (RRAM) Structures by Matthew L Chin...Effect of Atomic Layer Depositions (ALD)- Deposited Titanium Oxide (TiO2) Thickness on the Performance of Zr40Cu35Al15Ni10 (ZCAN)/ TiO2/Indium

  19. Deposition of conductive TiN shells on SiO2 nanoparticles with a fluidized bed ALD reactor

    Science.gov (United States)

    Didden, Arjen; Hillebrand, Philipp; Wollgarten, Markus; Dam, Bernard; van de Krol, Roel

    2016-02-01

    Conductive TiN shells have been deposited on SiO2 nanoparticles (10-20 nm primary particle size) with fluidized bed atomic layer deposition using TDMAT and NH3 as precursors. Analysis of the powders confirms that shell growth saturates at approximately 0.4 nm/cycle at TDMAT doses of >1.2 mmol/g of powder. TEM and XPS analysis showed that all particles were coated with homogeneous shells containing titanium. Due to the large specific surface area of the nanoparticles, the TiN shells rapidly oxidize upon exposure to air. Electrical measurements show that the partially oxidized shells are conducting, with apparent resistivity of approximately 11 kΩ cm. The resistivity of the powders is strongly influenced by the NH3 dose, with a smaller dose giving an order-of-magnitude higher resistivity.

  20. Deposition of conductive TiN shells on SiO{sub 2} nanoparticles with a fluidized bed ALD reactor

    Energy Technology Data Exchange (ETDEWEB)

    Didden, Arjen [Delft University of Technology, Faculty of Applied Sciences, Materials for Energy Conversion and Storage (Netherlands); Hillebrand, Philipp; Wollgarten, Markus [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Solar Fuels (Germany); Dam, Bernard; Krol, Roel van de, E-mail: roel.vandekrol@helmholtz-berlin.de [Delft University of Technology, Faculty of Applied Sciences, Materials for Energy Conversion and Storage (Netherlands)

    2016-02-15

    Conductive TiN shells have been deposited on SiO{sub 2} nanoparticles (10–20 nm primary particle size) with fluidized bed atomic layer deposition using TDMAT and NH{sub 3} as precursors. Analysis of the powders confirms that shell growth saturates at approximately 0.4 nm/cycle at TDMAT doses of >1.2 mmol/g of powder. TEM and XPS analysis showed that all particles were coated with homogeneous shells containing titanium. Due to the large specific surface area of the nanoparticles, the TiN shells rapidly oxidize upon exposure to air. Electrical measurements show that the partially oxidized shells are conducting, with apparent resistivity of approximately ∼11 kΩ cm. The resistivity of the powders is strongly influenced by the NH{sub 3} dose, with a smaller dose giving an order-of-magnitude higher resistivity.

  1. Micromechanical characterization of ALD thin films

    OpenAIRE

    Berdova, Maria

    2015-01-01

    Atomic layer deposited (ALD) films have become essential for various microelectromechanical systems (MEMS) due to their excellent properties: ALD films are conformal, uniform, dense, and pin-hole free. The main requirement for any film to be applied in MEMS is to exhibit good mechanical properties. Good mechanical properties mean that film has low residual stress, high fracture and interfacial strengths, and known elastic properties under applied mechanical load. MEMS devices are often subjec...

  2. Electrical characteristics of multilayered HfO2-Al2O3 charge trapping stacks deposited by ALD

    Science.gov (United States)

    Spassov, D.; Paskaleva, A.; Guziewicz, E.; Luka, G.; AKrajewski, T.; Kopalko, K.; Wierzbicka, A.; Blagoev, B.

    2016-10-01

    Electrical and charge trapping properties of atomic layer deposited HfO2-Al2O3 multilayer stacks with two different Al2O3 sublayer thicknesses were investigated regarding their implementation in charge trapping non-volatile memories. The effect of post deposition annealing in oxygen at 600°C is also studied. The decreasing Al2O3 thickness increases the stack's dielectric constant and the density of the initial positive oxide charge. The initial oxide charge increases after annealing to ∼6×1012 cm-2 and changes its sign to negative for the stacks with thicker Al2O3. The annealing enhances the dielectric constant of the stacks and reduces their thickness preserving the amorphous status. Nevertheless the annealing is not beneficial for the stacks with thicker Al2O3 as it considerably increases leakage currents. Conduction mechanisms in stacks were considered in terms of hopping conduction at low electric fields, and Fowler- Nordheim tunnelling, Schottky emission and Poole-Frenkel effect at higher ones. Maximum memory windows of about 12 and 16V were obtained for the as-grown structures with higher and lower Al2O3 content, respectively. In latter case additional improvement (the memory window increase up to 23V) is achieved by the annealing.

  3. Developments in plasma enhanced spatial ALD for high throughput applications [3.04

    NARCIS (Netherlands)

    Creyghton, Y.; Illiberi, A.; Mione, M.; Boekel, W. van; Debernardi, N.; Seitz, M.; Bruele, F. van den; Poodt, P.; Roozeboom,F.

    2016-01-01

    Atomic layer deposition by means of spatial separation of reactive gases is emerging as an industrial manufacturing technology. Integration of non-thermal plasma in spatial ALD machines will further expand the process window towards lower operation temperatures and specific materials requiring radic

  4. Reaction network analysis for thin film deposition processes

    Science.gov (United States)

    Ramakrishnasubramanian, Krishnaprasath

    Understanding the growth of thin films produced by Atomic Layer Deposition (ALD) and Chemical Vapor Deposition (CVD) has been one of the most important challenge for surface chemists over the last two to three decades. There has been a lack of complete understanding of the surface chemistry behind these systems due to the dearth of experimental reaction kinetics data available. The data that do exist are generally derived through quantum computations. Thus, it becomes ever so important to develop a deposition model which not only predicts the bulk film chemistry but also explains its self-limiting nature and growth surface stability without the use of reaction rate data. The reaction network analysis tools developed in this thesis are based on a reaction factorization approach that aims to decouple the reaction rates by accounting for the chemical species surface balance dynamic equations. This process eliminates the redundant dynamic modes and identifies conserved modes as reaction invariants. The analysis of these invariants is carried out using a Species-Reaction (S-R) graph approach which also serves to simplify the representation of the complex reaction network. The S-R graph is self explanatory and consistent for all systems. The invariants can be easily extracted from the S-R graph by following a set of straightforward rules and this is demonstrated for the CVD of gallium nitride and the ALD of gallium arsenide. We propose that understanding invariants through these S-R graphs not only provides us with the physical significance of conserved modes but also give us a better insight into the deposition mechanism.

  5. Crystallinity of inorganic films grown by atomic layer deposition: Overview and general trends

    Science.gov (United States)

    Miikkulainen, Ville; Leskelä, Markku; Ritala, Mikko; Puurunen, Riikka L.

    2013-01-01

    Atomic layer deposition (ALD) is gaining attention as a thin film deposition method, uniquely suitable for depositing uniform and conformal films on complex three-dimensional topographies. The deposition of a film of a given material by ALD relies on the successive, separated, and self-terminating gas-solid reactions of typically two gaseous reactants. Hundreds of ALD chemistries have been found for depositing a variety of materials during the past decades, mostly for inorganic materials but lately also for organic and inorganic-organic hybrid compounds. One factor that often dictates the properties of ALD films in actual applications is the crystallinity of the grown film: Is the material amorphous or, if it is crystalline, which phase(s) is (are) present. In this thematic review, we first describe the basics of ALD, summarize the two-reactant ALD processes to grow inorganic materials developed to-date, updating the information of an earlier review on ALD [R. L. Puurunen, J. Appl. Phys. 97, 121301 (2005)], and give an overview of the status of processing ternary compounds by ALD. We then proceed to analyze the published experimental data for information on the crystallinity and phase of inorganic materials deposited by ALD from different reactants at different temperatures. The data are collected for films in their as-deposited state and tabulated for easy reference. Case studies are presented to illustrate the effect of different process parameters on crystallinity for representative materials: aluminium oxide, zirconium oxide, zinc oxide, titanium nitride, zinc zulfide, and ruthenium. Finally, we discuss the general trends in the development of film crystallinity as function of ALD process parameters. The authors hope that this review will help newcomers to ALD to familiarize themselves with the complex world of crystalline ALD films and, at the same time, serve for the expert as a handbook-type reference source on ALD processes and film crystallinity.

  6. Precise Nanoscale Surface Modification and Coating of Macroscale Objects: Open-Environment in Loco Atomic Layer Deposition on an Automobile.

    Science.gov (United States)

    Mousa, Moataz Bellah M; Oldham, Christopher J; Parsons, Gregory N

    2015-09-09

    The fundamental chemical reaction conditions that define atomic layer deposition (ALD) can be achieved in an open environment on a macroscale surface too large and complex for typical laboratory reactor-based ALD. We describe the concept of in loco ALD using conventional modulated reactant flow through a surface-mounted "ALD delivery head" to form a precise nanoscale Al2O3 film on the window of a parked automobile. Analysis confirms that the processes eliminated ambient water contamination and met other conditions that define ALD growth. Using this tool, we demonstrate open-ambient patterned deposition, metal corrosion protection, and polymer surface modification.

  7. Characterization of ALD Processed Gallium Doped TiO2 Hole Blocking Layer in an Inverted Organic Solar Cell

    Science.gov (United States)

    Lee, Eun Ju; Ryu, Sang Ouk

    2016-10-01

    To improve power conversion efficiency (PCE) of inverted structure organic solar cells a buffer layer, a hole blocking layer (HBL) was introduced between cathode and active photovoltaic layer. Gallium (Ga) doped TiO2 as a HBL was fabricated by means of atomic layer deposition. X-ray photoelectron spectroscopy showed the highest Ga-Ti complex binding characteristics was achieved at 5% doping concentration. Gallium doped TiO2 layer exhibited over 94% of optical transmittance at the process temperature of 200°C. The resulting PCE of inverted structure organic solar cell having 5% doping in the hole block layer was 2.7%. The PCE was improved 35% compared to the cell without gallium doping.

  8. Characterization of ALD Processed Gallium Doped TiO2 Hole Blocking Layer in an Inverted Organic Solar Cell

    Science.gov (United States)

    Lee, Eun Ju; Ryu, Sang Ouk

    2017-02-01

    To improve power conversion efficiency (PCE) of inverted structure organic solar cells a buffer layer, a hole blocking layer (HBL) was introduced between cathode and active photovoltaic layer. Gallium (Ga) doped TiO2 as a HBL was fabricated by means of atomic layer deposition. X-ray photoelectron spectroscopy showed the highest Ga-Ti complex binding characteristics was achieved at 5% doping concentration. Gallium doped TiO2 layer exhibited over 94% of optical transmittance at the process temperature of 200°C. The resulting PCE of inverted structure organic solar cell having 5% doping in the hole block layer was 2.7%. The PCE was improved 35% compared to the cell without gallium doping.

  9. Deposition of ultra thin CuInS₂ absorber layers by ALD for thin film solar cells at low temperature (down to 150 °C).

    Science.gov (United States)

    Schneider, Nathanaelle; Bouttemy, Muriel; Genevée, Pascal; Lincot, Daniel; Donsanti, Frédérique

    2015-02-01

    Two new processes for the atomic layer deposition of copper indium sulfide (CuInS₂) based on the use of two different sets of precursors are reported. Metal chloride precursors (CuCl, InCl₃) in combination with H2S imply relatively high deposition temperature (Tdep = 380 °C), and due to exchange reactions, CuInS₂ stoechiometry was only achieved by depositing In₂S3 layers on a CuxS film. However, the use of acac- metal precursors (Cu(acac)₂, In(acac)₃) allows the direct deposition of CuInS₂ at temperature as low as 150 °C, involving in situ copper-reduction, exchange reaction and diffusion processes. The morphology, crystallographic structure, chemical composition and optical band gap of thin films were investigated using scanning electronic microscope, x-ray diffraction under grazing incidence conditions, x-ray fluorescence, energy dispersive spectrometry, secondary ion mass spectrometry, x-ray photoelectron spectroscopy and UV-vis spectroscopy. Films were implemented as ultra-thin absorbers in a typical CIS-solar cell architecture and allowed conversion efficiencies up to 2.8%.

  10. Deposition of ultra thin CuInS2 absorber layers by ALD for thin film solar cells at low temperature (down to 150 °C)

    Science.gov (United States)

    Schneider, Nathanaelle; Bouttemy, Muriel; Genevée, Pascal; Lincot, Daniel; Donsanti, Frédérique

    2015-02-01

    Two new processes for the atomic layer deposition of copper indium sulfide (CuInS2) based on the use of two different sets of precursors are reported. Metal chloride precursors (CuCl, InCl3) in combination with H2S imply relatively high deposition temperature (Tdep = 380 °C), and due to exchange reactions, CuInS2 stoechiometry was only achieved by depositing In2S3 layers on a CuxS film. However, the use of acac- metal precursors (Cu(acac)2, In(acac)3) allows the direct deposition of CuInS2 at temperature as low as 150 °C, involving in situ copper-reduction, exchange reaction and diffusion processes. The morphology, crystallographic structure, chemical composition and optical band gap of thin films were investigated using scanning electronic microscope, x-ray diffraction under grazing incidence conditions, x-ray fluorescence, energy dispersive spectrometry, secondary ion mass spectrometry, x-ray photoelectron spectroscopy and UV-vis spectroscopy. Films were implemented as ultra-thin absorbers in a typical CIS-solar cell architecture and allowed conversion efficiencies up to 2.8%.

  11. Vapour sensitivity of an ALD hierarchical photonic structure inspired by Morpho.

    Science.gov (United States)

    Poncelet, Olivier; Tallier, Guillaume; Mouchet, Sébastien R; Crahay, André; Rasson, Jonathan; Kotipalli, Ratan; Deparis, Olivier; Francis, Laurent A

    2016-05-09

    The unique architecture of iridescent Morpho butterfly scales is known to exhibit different optical responses to various vapours. However, the mechanism behind this phenomenon is not fully quantitatively understood. This work reports on process developments in the micro-fabrication of a Morpho-inspired photonic structure in atomic layer deposited (ALD) materials in order to investigate the vapour optical sensitivity of such artificial nanostructures. By developing recipes for dry and wet etching of ALD oxides, we micro-fabricated two structures: one combining Al2O3 and TiO2, and the other combining Al2O3 and HfO2. For the first time, we report the optical response of such ALD Morpho-like structures measured under a controlled flow of either ethanol or isopropyl alcohol (IPA) vapour. In spite of the small magnitude of the effect, the results show a selective vapour response (depending on the materials used).

  12. In situ ALD experiments with synchrotron radiation photoelectron spectroscopy

    Science.gov (United States)

    Tallarida, Massimo; Schmeisser, Dieter

    2012-07-01

    In this contribution, we describe some features of atomic layer deposition (ALD) investigated by means of synchrotron radiation photoelemission spectroscopy (SR-PES). In particular, we show how the surface sensitivity of SR-PES combined with the in situ nature of our investigations can point out interactions between the substrate and ALD precursors. We observed changes on all substrates investigated, included Si, GaAs, Ru and their surface oxides. These interactions are extremely important during the first ALD cycles and induce modifications in the substrate, which might lead to its functionality enhancement.

  13. Synthesis of ALD zinc oxide and thin film materials optimization for UV photodetector applications

    Science.gov (United States)

    Tapily, Kandabara Nouhoum

    Zinc oxide (ZnO) is a direct, wide bandgap semiconductor material. It is thermodynamically stable in the wurtzite structure at ambient temperature conditions. ZnO has very interesting optical and electrical properties and is a suitable candidate for numerous optoelectronic applications such as solar cells, LEDs and UV-photodetectors. ZnO is a naturally n-type semiconductor. Due to the lack of reproducible p-type ZnO, achieving good homojunction ZnO-based photodiodes such as UV-photodetectors remains a challenge. Meanwhile, heterojunction structures of ZnO with p-type substrates such as SiC, GaN, NiO, AlGaN, Si etc. are used; however, those heterojunction diodes suffer from low efficiencies. ZnO is an n-type material with numerous intrinsic defect levels responsible for the electrical and optical behaviors. Presently, there is no clear consensus about the origin of those defects. In this work, ZnO was synthesized by atomic layer deposition (ALD). ALD is a novel deposition technique suitable for nanotechnology engineering that provides unique features such as precise control of ZnO thin film with atomic resolution, high uniformity, good conformity and high aspect ratio. Using this novel deposition technique, the ALD ZnO deposition process was developed and optimized using diethyl zinc as the precursor for zinc and water vapor as the oxygen source. In order to optimize the film quality for use in electronic applications, the physical, mechanical and electrical properties were investigated. The structural and mechanical properties of the ALD ZnO thin films were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), spectroscopic Ellipsometry, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV-VIS absorption and nanoindentation. The electrical characterizations were performed using C-V, I-V, DLTS, Hall Effect, and four-point probe. The intrinsic defects responsible

  14. Area-selective atomic layer deposition of platinum using photosensitive polyimide

    Science.gov (United States)

    Vervuurt, René H. J.; Sharma, Akhil; Jiao, Yuqing; Kessels, Wilhelmus (Erwin M. M.; Bol, Ageeth A.

    2016-10-01

    Area-selective atomic layer deposition (AS-ALD) of platinum (Pt) was studied using photosensitive polyimide as a masking layer. The polyimide films were prepared by spin-coating and patterned using photolithography. AS-ALD of Pt using poly(methyl-methacrylate) (PMMA) masking layers was used as a reference. The results show that polyimide has excellent selectivity towards the Pt deposition, after 1000 ALD cycles less than a monolayer of Pt is deposited on the polyimide surface. The polyimide film could easily be removed after ALD using a hydrogen plasma, due to a combination of weakening of the polyimide resist during Pt ALD and the catalytic activity of Pt traces on the polyimide surface. Compared to PMMA for AS-ALD of Pt, polyimide has better temperature stability. This resulted in an improved uniformity of the Pt deposits and superior definition of the Pt patterns. In addition, due to the absence of reflow contamination using polyimide the nucleation phase during Pt ALD is drastically shortened. Pt patterns down to 3.5 μm were created with polyimide, a factor of ten smaller than what is possible using PMMA, at the typical Pt ALD processing temperature of 300 °C. Initial experiments indicate that after further optimization of the polyimide process Pt features down to 100 nm should be possible, which makes AS-ALD of Pt using photosensitive polyimide a promising candidate for patterning at the nanoscale.

  15. Probing initial-stages of ALD growth with dynamic in situ spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Muneshwar, Triratna, E-mail: muneshwa@ualberta.ca; Cadien, Ken

    2015-02-15

    Graphical abstract: - Highlights: • Dynamic in situ spectroscopic ellipsometry to study ALD growth initiation. • Sub-monolayer ALD growth is modeled as diffusive film growth mode. • Bruggeman's EMA model used to analyze d-iSE data. • Plasma enhanced ALD of ZrN is presented as example. • Surface coverage of ZrN film is calculated after every ALD cycle. - Abstract: The initial stages of ALD surface reactions are probed using dynamic in situ spectroscopic ellipsometry (d-iSE) technique during plasma-enhanced ALD of zirconium nitride (ZrN) thin films in spectral range of 0.73–6.4 eV. The measured change in the ellipsometry parameter Δ, with every precursor (TDMAZr) and reactant (forming gas plasma) exposure is interpreted as the combined effect of film growth and change in surface chemistry during ALD. We present application of Bruggeman's effective-medium approximation (B-EMA) in the analysis of d-iSE data to determine fractional surface coverage (θ) of ALD grown film at the end of every deposition cycle. During the deposition of first few ZrN monolayers, d-iSE datasets are analyzed on the basis of surface diffusion enhanced ALD growth, where the surface adsorbed precursor molecules can diffuse over substrate surface to occupy energetically favorable surface sites. The determined surface coverage of ZrN films highlights the effects of substrate enhanced ALD growth.

  16. Atomic layer deposition of Ru from CpRu(CO)(2)Et using O-2 gas and O-2 plasma

    NARCIS (Netherlands)

    Leick, N.; Verkuijlen, R. O. F.; Lamagna, L.; Langereis, E.; Rushworth, S.; Roozeboom, F.; M. C. M. van de Sanden,; Kessels, W. M. M.

    2011-01-01

    The metalorganic precursor cyclopentadienylethyl(dicarbonyl)ruthenium (CpRu(CO)(2)Et) was used to develop an atomic layer deposition (ALD) process for ruthenium. O-2 gas and O-2 plasma were employed as reactants. For both processes, thermal and plasma-assisted ALD, a relatively high growth-per-cycle

  17. High-quality tungsten films by hotwire-assisted CVD/ALD at low temperature

    NARCIS (Netherlands)

    Kovalgin, Alexey Y.

    2016-01-01

    There is a growing interest in atomic layer deposition (ALD) of metals for ultra-large-scale integrated circuit (ULSIC) manufacturing. Radical-enhanced ALD (REALD) utilizing plasma (PEALD) has been proposed to grow a number of metals. In our work, we investigate an alternative approach to REALD with

  18. Polymer LED Encapsulation by means of Plasma-Assisted ALD Al2O3 films

    NARCIS (Netherlands)

    Creatore, M.; Keuning, W.; Langereis, E.; Lifka, H.; Van de Weijer, P.; Van de Sanden, M.C.M.; Kessels, W.M.M.

    2011-01-01

    Within a 500h test, ALD encapsulated poly-LEDs show approximately half the black spot density of plasma deposited a-SiNx:H (300 nm thick) encapsulated devices. The black spot density is further reduced ifthe a-SiNx:H layer is coupled with an ALD layer and such decrease is accompanied by a massive re

  19. ALDS 1978 panel review. [PNL

    Energy Technology Data Exchange (ETDEWEB)

    Hall, D.L. (ed.)

    1979-08-01

    Pacific Northwest Laboratory (PNL) is examining the analysis of large data sets (ALDS). After one year's work, a panel was convened to evaluate the project. This document is the permanent record of that panel review. It consists of edited transcripts of presentations made to the panel by the PNL staff, a summary of the responses of the panel to these presentations, and PNL's plans for the development of the ALDS project. The representations of the PNL staff described various aspects of the project and/or the philosophy surrounding the project. Supporting materials appear in appendixes. 20 figures, 4 tables. (RWR)

  20. Optical characteristics of H{sub 2}O-based and O{sub 3}-based HfO{sub 2} films deposited by ALD using spectroscopy ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Xiaojiao; Liu, Hongxia; Zhong, Bo; Fei, Chenxi; Wang, Xing; Wang, Qianqiong [Xidian University, School of Microelectronics, Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xi' an (China)

    2015-06-15

    Optical properties of thin atomic layer-deposited HfO{sub 2} films grown by H{sub 2}O and O{sub 3} are analyzed by variable angle spectroscopic ellipsometry. By investigating the dielectric constant, it is found that a higher real part of the dielectric constant (ε {sub 1}) value is observed for H{sub 2}O-based film due to less silicate component in the film. Careful examination of the log scale of imaginary part of the dielectric constant (ε {sub 2}) leads to the conclusion that the absorption features in the energy range of 3.2-5.35 eV originate from the interface layer between the silicon substrate and the native oxide. In particular, O{sub 3}-based gate stacks have less sub-band gap defect states besides the silicon's critical features. Moreover, a larger high-frequency dielectric constant, direct and indirect band gap values are obtained for O{sub 3}-based film. Meanwhile, suitable valence band offsets (3.38 and 3.55 eV) and conduction band offsets (1.58 and 1.47 eV) are obtained for H{sub 2}O- and O{sub 3}-based HfO{sub 2} gate stacks, respectively, indicating both type of dielectric films can provide sufficient tunneling barriers for both electrons and holes. (orig.)

  1. Ellipsometry and XPS comparative studies of thermal and plasma enhanced atomic layer deposited Al2O3-films

    Directory of Open Access Journals (Sweden)

    Jörg Haeberle

    2013-11-01

    Full Text Available We report on results on the preparation of thin (2O3 films on silicon substrates using thermal atomic layer deposition (T-ALD and plasma enhanced atomic layer deposition (PE-ALD in the SENTECH SI ALD LL system. The T-ALD Al2O3 layers were deposited at 200 °C, for the PE-ALD films we varied the substrate temperature range between room temperature (rt and 200 °C. We show data from spectroscopic ellipsometry (thickness, refractive index, growth rate over 4” wafers and correlate them to X-ray photoelectron spectroscopy (XPS results. The 200 °C T-ALD and PE-ALD processes yield films with similar refractive indices and with oxygen to aluminum elemental ratios very close to the stoichiometric value of 1.5. However, in both also fragments of the precursor are integrated into the film. The PE-ALD films show an increased growth rate and lower carbon contaminations. Reducing the deposition temperature down to rt leads to a higher content of carbon and CH-species. We also find a decrease of the refractive index and of the oxygen to aluminum elemental ratio as well as an increase of the growth rate whereas the homogeneity of the film growth is not influenced significantly. Initial state energy shifts in all PE-ALD samples are observed which we attribute to a net negative charge within the films.

  2. Ellipsometry and XPS comparative studies of thermal and plasma enhanced atomic layer deposited Al2O3-films.

    Science.gov (United States)

    Haeberle, Jörg; Henkel, Karsten; Gargouri, Hassan; Naumann, Franziska; Gruska, Bernd; Arens, Michael; Tallarida, Massimo; Schmeißer, Dieter

    2013-01-01

    We report on results on the preparation of thin (<100 nm) aluminum oxide (Al2O3) films on silicon substrates using thermal atomic layer deposition (T-ALD) and plasma enhanced atomic layer deposition (PE-ALD) in the SENTECH SI ALD LL system. The T-ALD Al2O3 layers were deposited at 200 °C, for the PE-ALD films we varied the substrate temperature range between room temperature (rt) and 200 °C. We show data from spectroscopic ellipsometry (thickness, refractive index, growth rate) over 4" wafers and correlate them to X-ray photoelectron spectroscopy (XPS) results. The 200 °C T-ALD and PE-ALD processes yield films with similar refractive indices and with oxygen to aluminum elemental ratios very close to the stoichiometric value of 1.5. However, in both also fragments of the precursor are integrated into the film. The PE-ALD films show an increased growth rate and lower carbon contaminations. Reducing the deposition temperature down to rt leads to a higher content of carbon and CH-species. We also find a decrease of the refractive index and of the oxygen to aluminum elemental ratio as well as an increase of the growth rate whereas the homogeneity of the film growth is not influenced significantly. Initial state energy shifts in all PE-ALD samples are observed which we attribute to a net negative charge within the films.

  3. Low temperature temporal and spatial atomic layer deposition of TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Aghaee, Morteza, E-mail: m.aghaee@tue.nl; Maydannik, Philipp S. [ASTRaL Group, Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Johansson, Petri; Kuusipalo, Jurkka [Paper Converting and Packaging Technology, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Creatore, Mariadriana [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Homola, Tomáš; Cameron, David C. [R& D Center for Low-Cost Plasma and Nanotechnology Surface Modification, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic)

    2015-07-15

    Titanium dioxide films were grown by atomic layer deposition (ALD) using titanium tetraisopropoxide as a titanium precursor and water, ozone, or oxygen plasma as coreactants. Low temperatures (80–120 °C) were used to grow moisture barrier TiO{sub 2} films on polyethylene naphthalate. The maximum growth per cycle for water, ozone, and oxygen plasma processes were 0.33, 0.12, and 0.56 Å/cycle, respectively. X-ray photoelectron spectrometry was used to evaluate the chemical composition of the layers and the origin of the carbon contamination was studied by deconvoluting carbon C1s peaks. In plasma-assisted ALD, the film properties were dependent on the energy dose supplied by the plasma. TiO{sub 2} films were also successfully deposited by using a spatial ALD (SALD) system based on the results from the temporal ALD. Similar properties were measured compared to the temporal ALD deposited TiO{sub 2}, but the deposition time could be reduced using SALD. The TiO{sub 2} films deposited by plasma-assisted ALD showed better moisture barrier properties than the layers deposited by thermal processes. Water vapor transmission rate values lower than 5 × 10{sup −4} g day{sup −1} m{sup −2} (38 °C and 90% RH) was measured for 20 nm of TiO{sub 2} film deposited by plasma-assisted ALD.

  4. Incomplete elimination of precursor ligands during atomic layer deposition of zinc-oxide, tin-oxide, and zinc-tin-oxide

    Science.gov (United States)

    Mackus, Adriaan J. M.; MacIsaac, Callisto; Kim, Woo-Hee; Bent, Stacey F.

    2017-02-01

    For atomic layer deposition (ALD) of doped, ternary, and quaternary materials achieved by combining multiple binary ALD processes, it is often difficult to correlate the material properties and growth characteristics with the process parameters due to a limited understanding of the underlying surface chemistry. In this work, in situ Fourier transform infrared (FTIR) spectroscopy was employed during ALD of zinc-oxide, tin-oxide, and zinc-tin-oxide (ZTO) with the precursors diethylzinc (DEZ), tetrakis(dimethylamino)tin (TDMASn), and H2O. The main aim was to investigate the molecular basis for the nucleation delay during ALD of ZTO, observed when ZnO ALD is carried out after SnO2 ALD. Gas-phase FTIR spectroscopy showed that dimethylamine, the main reaction product of the SnO2 ALD process, is released not only during SnO2 ALD but also when depositing ZnO after SnO2, indicating incomplete removal of the ligands of the TDMASn precursor from the surface. Transmission FTIR spectroscopy performed during ALD on SiO2 powder revealed that a significant fraction of the ligands persist during both SnO2 and ZnO ALD. These observations provide experimental evidence for a recently proposed mechanism, based on theoretical calculations, suggesting that the elimination of precursor ligands is often not complete. In addition, it was found that the removal of precursor ligands by H2O exposure is even less effective when ZnO ALD is carried out after SnO2 ALD, which likely causes the nucleation delay in ZnO ALD during the deposition of ZTO. The underlying mechanisms and the consequences of the incomplete elimination of precursor ligands are discussed.

  5. Homogeneous transparent conductive ZnO:Ga by ALD for large LED wafers

    Energy Technology Data Exchange (ETDEWEB)

    Szabó, Zoltán; Baji, Zsófia [MTA EK Institute of Technical Physics and Materials Science, Konkoly Thege M. út 29-33, 1121 Budapest (Hungary); Basa, Péter [Semilab Semiconductor Physics Laboratory Co. Ltd., Prielle K. u. 2, H-1117 Budapest (Hungary); Czigány, Zsolt; Bársony, István [MTA EK Institute of Technical Physics and Materials Science, Konkoly Thege M. út 29-33, 1121 Budapest (Hungary); Wang, Hsin-Ying [Epistar corporation No 5, Li-hsin 5th Rd., Hsinchu Science Park, Hsinchu 300, Taiwan (China); Volk, János, E-mail: volk@mfa.kfki.hu [MTA EK Institute of Technical Physics and Materials Science, Konkoly Thege M. út 29-33, 1121 Budapest (Hungary)

    2016-08-30

    Highlights: • Highly conductive, transparent GZO layers were deposited by ALD. • The ALD layers show superior thickness and sheet resistance homogeneity for 4” wafers. • A two-step ALD deposition technique was proposed and demonstrated to improve the quality of GZO/p-GaN interface. - Abstract: Highly conductive and uniform Ga doped ZnO (GZO) films were prepared by atomic layer deposition (ALD) as transparent conductive layers for InGaN/GaN LEDs. The optimal Ga doping concentration was found to be 3 at%. Even for 4” wafers, the TCO layer shows excellent homogeneity of film resistivity (0.8 %) according to Eddy current and spectroscopic ellipsometry mapping. This makes ALD a favourable technique over concurrent methods like MBE and PLD where the up-scaling is problematic. In agreement with previous studies, it was found that by an annealing treatment the quality of the GZO/p-GaN interface can be improved, although it causes the degradation of TCO conductivity. Therefore, a two-step ALD deposition technique was proposed and demonstrated: a “buffer layer” deposited and annealed first was followed by a second deposition step to maintain the high conductivity of the top layer.

  6. Surface preparation for ALD of High-k dielectrics on indium gallium arsenide

    Science.gov (United States)

    Melitz, Wilhelm

    The key for a successful gate-first process is when subsequent processing steps cannot degrade the semiconductor, the dielectric, or the oxide-semiconductor interfaces. For silicon, the only commercial ALD high-k fabrication process, which avoids processing induced damage, is a replacement gate process (a type of gate-last process). While preparing silicon for gate-last processing is straightforward, the key to a gate-last process for III-V semiconductors is the order and cleanliness of the III-V channel prior to dielectric deposition. Aggressive oxide thickness reduction (equivalent oxide thickness, or EOT, scaling) is needed to fabricate small gate length devices with small subthreshold swings. Furthermore, aggressive EOT scaling requires a very high uniform ALD nucleation density, with no pinholes due to surface contaminants. The key barrier to solving a very practical problem is a surface chemistry challenge: develop a chemical process which removes nearly all air induced defects and contaminants and leaves the III-V surface flat and electrically active for high nucleation density ALD gate oxide deposition, which unpins the Fermi level. The following study uses scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) to observe the removal of the oxide layer and restoration of the clean InGaAs surface reconstruction with atomic hydrogen cleaning, allowing for a gate-last or replacement-gate process. Along with surface cleaning STM and STS was used to characterize the initial passivation of InGaAs surfaces via ALD of trimethyl aluminum (TMA). The substrate temperature and initial surface reconstruction was critical to forming an unpinned passivation layer with a high nucleation density. A method was developed to use Kelvin probe force microscopy (KPFM) as a tool for insightful feedback on the electrostatics of scaled MOSFET devices. KPFM is a unique technique for providing two-dimensional potential profiles inside a working device. A

  7. Low-temperature atomic layer deposition of TiO{sub 2} thin layers for the processing of memristive devices

    Energy Technology Data Exchange (ETDEWEB)

    Porro, Samuele, E-mail: samuele.porro@polito.it; Conti, Daniele; Guastella, Salvatore; Ricciardi, Carlo [Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Jasmin, Alladin; Pirri, Candido F. [Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy and Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, C.so Trento 21, 10129 Torino (Italy); Bejtka, Katarzyna; Perrone, Denis; Chiolerio, Alessandro [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, C.so Trento 21, 10129 Torino (Italy)

    2016-01-15

    Atomic layer deposition (ALD) represents one of the most fundamental techniques capable of satisfying the strict technological requirements imposed by the rapidly evolving electronic components industry. The actual scaling trend is rapidly leading to the fabrication of nanoscaled devices able to overcome limits of the present microelectronic technology, of which the memristor is one of the principal candidates. Since their development in 2008, TiO{sub 2} thin film memristors have been identified as the future technology for resistive random access memories because of their numerous advantages in producing dense, low power-consuming, three-dimensional memory stacks. The typical features of ALD, such as self-limiting and conformal deposition without line-of-sight requirements, are strong assets for fabricating these nanosized devices. This work focuses on the realization of memristors based on low-temperature ALD TiO{sub 2} thin films. In this process, the oxide layer was directly grown on a polymeric photoresist, thus simplifying the fabrication procedure with a direct liftoff patterning instead of a complex dry etching process. The TiO{sub 2} thin films deposited in a temperature range of 120–230 °C were characterized via Raman spectroscopy and x-ray photoelectron spectroscopy, and electrical current–voltage measurements taken in voltage sweep mode were employed to confirm the existence of resistive switching behaviors typical of memristors. These measurements showed that these low-temperature devices exhibit an ON/OFF ratio comparable to that of a high-temperature memristor, thus exhibiting similar performances with respect to memory applications.

  8. Fast method for reactor and feature scale coupling in ALD and CVD

    Energy Technology Data Exchange (ETDEWEB)

    Yanguas-Gil, Angel; Elam, Jeffrey W.

    2017-08-08

    Transport and surface chemistry of certain deposition techniques is modeled. Methods provide a model of the transport inside nanostructures as a single-particle discrete Markov chain process. This approach decouples the complexity of the surface chemistry from the transport model, thus allowing its application under general surface chemistry conditions, including atomic layer deposition (ALD) and chemical vapor deposition (CVD). Methods provide for determination of determine statistical information of the trajectory of individual molecules, such as the average interaction time or the number of wall collisions for molecules entering the nanostructures as well as to track the relative contributions to thin-film growth of different independent reaction pathways at each point of the feature.

  9. A Review of Atomic Layer Deposition for Nanoscale Devices

    Directory of Open Access Journals (Sweden)

    Edy Riyanto

    2012-12-01

    Full Text Available Atomic layer deposition (ALD is a thin film growth technique that utilizes alternating, self-saturation chemical reactions between gaseous precursors to achieve a deposited nanoscale layers. It has recently become a subject of great interest for ultrathin film deposition in many various applications such as microelectronics, photovoltaic, dynamic random access memory (DRAM, and microelectromechanic system (MEMS. By using ALD, the conformability and extreme uniformity of layers can be achieved in low temperature process. It facilitates to be deposited onto the surface in many variety substrates that have low melting temperature. Eventually it has advantages on the contribution to the wider nanodevices.

  10. Effect of atomic layer deposition growth temperature on the interfacial characteristics of HfO{sub 2}/p-GaAs metal-oxide-semiconductor capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.; Zhang, Y. M.; Zhang, Y. M.; Lv, H. L., E-mail: hllv@mail.xidian.edu.cn [School of Microelectronics, Xidian University and Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xi' an 710071 (China)

    2014-12-14

    The effect of atomic layer deposition (ALD) growth temperature on the interfacial characteristics of p-GaAs MOS capacitors with ALD HfO{sub 2} high-k dielectric using tetrakis(ethylmethyl)amino halfnium precursor is investigated in this study. Using the combination of capacitance-voltage (C-V) and X-ray photoelectron spectroscopy (XPS) measurements, ALD growth temperature is found to play a large role in controlling the reaction between interfacial oxides and precursor and ultimately determining the interface properties. The reduction of surface oxides is observed to be insignificant for ALD at 200 °C, while markedly pronounced for growth at 300 °C. The corresponding C-V characteristics are also shown to be ALD temperature dependent and match well with the XPS results. Thus, proper ALD process is crucial in optimizing the interface quality.

  11. Influence of the Oxidant on the Chemical and Field-Effect Passivation of Si by ALD Al2O3

    NARCIS (Netherlands)

    Dingemans, G.; Terlinden, N. M.; Pierreux, D.; Profijt, H. B.; M. C. M. van de Sanden,; Kessels, W. M. M.

    2011-01-01

    Differences in Si surface passivation by aluminum oxide (Al2O3) films synthesized using H2O and O-3-based thermal atomic layer deposition (ALD) and plasma ALD have been revealed. A low interface defect density of D-it = similar to 1011 eV(-1) cm(-2) was obtained after annealing, independent of the o

  12. Electrocatalytic activity of Pt grown by ALD on carbon nanotubes for Si-based DMFC applications

    DEFF Research Database (Denmark)

    Johansson, Alicia Charlotte; Dalslet, Bjarke Thomas; Yang, R.B.

    2012-01-01

    We present an anode design for silicon-based direct methanol fuel cell (DMFC) applications. Platinum was deposited conformally by atomic layer deposition (ALD) onto vertically aligned, nitrogendoped multi-walled carbon nanotubes (MWCNTs) grown on porous silicon. The deposition was carried out...... that ALD could be a MEMS compatible deposition technique for Si-based fuel cell applications. © The Electrochemical Society....... in a top-flow ALD reactor at 250°C, using MeCpPtMe3 and O2 as precursors. The anode was tested for the methanol oxidation reaction (MOR) in a three-electrode electrochemical set-up and it showed improved catalytic activity compared to a reference sample of Pt deposited on flat Si. It is demonstrated...

  13. Recent progress of atomic layer deposition on polymeric materials.

    Science.gov (United States)

    Guo, Hong Chen; Ye, Enyi; Li, Zibiao; Han, Ming-Yong; Loh, Xian Jun

    2017-01-01

    As a very promising surface coating technology, atomic layer deposition (ALD) can be used to modify the surfaces of polymeric materials for improving their functions and expanding their application areas. Polymeric materials vary in surface functional groups (number and type), surface morphology and internal structure, and thus ALD deposition conditions that typically work on a normal solid surface, usually do not work on a polymeric material surface. To date, a large variety of research has been carried out to investigate ALD deposition on various polymeric materials. This paper aims to provide an in-depth review of ALD deposition on polymeric materials and its applications. Through this review, we will provide a better understanding of surface chemistry and reaction mechanism for controlled surface modification of polymeric materials by ALD. The integrated knowledge can aid in devising an improved way in the reaction between reactant precursors and polymer functional groups/polymer backbones, which will in turn open new opportunities in processing ALD materials for better inorganic/organic film integration and potential applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Modeling and optimization of atomic layer deposition processes on vertically aligned carbon nanotubes.

    Science.gov (United States)

    Yazdani, Nuri; Chawla, Vipin; Edwards, Eve; Wood, Vanessa; Park, Hyung Gyu; Utke, Ivo

    2014-01-01

    Many energy conversion and storage devices exploit structured ceramics with large interfacial surface areas. Vertically aligned carbon nanotube (VACNT) arrays have emerged as possible scaffolds to support large surface area ceramic layers. However, obtaining conformal and uniform coatings of ceramics on structures with high aspect ratio morphologies is non-trivial, even with atomic layer deposition (ALD). Here we implement a diffusion model to investigate the effect of the ALD parameters on coating kinetics and use it to develop a guideline for achieving conformal and uniform thickness coatings throughout the depth of ultra-high aspect ratio structures. We validate the model predictions with experimental data from ALD coatings of VACNT arrays. However, the approach can be applied to predict film conformality as a function of depth for any porous topology, including nanopores and nanowire arrays.

  15. Modeling and optimization of atomic layer deposition processes on vertically aligned carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Nuri Yazdani

    2014-03-01

    Full Text Available Many energy conversion and storage devices exploit structured ceramics with large interfacial surface areas. Vertically aligned carbon nanotube (VACNT arrays have emerged as possible scaffolds to support large surface area ceramic layers. However, obtaining conformal and uniform coatings of ceramics on structures with high aspect ratio morphologies is non-trivial, even with atomic layer deposition (ALD. Here we implement a diffusion model to investigate the effect of the ALD parameters on coating kinetics and use it to develop a guideline for achieving conformal and uniform thickness coatings throughout the depth of ultra-high aspect ratio structures. We validate the model predictions with experimental data from ALD coatings of VACNT arrays. However, the approach can be applied to predict film conformality as a function of depth for any porous topology, including nanopores and nanowire arrays.

  16. Determination of interfacial layers in high - k ALD nanolaminate materials by ARXPS and SRXPS measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Wyrodek, Jakub; Tallarida, Massimo; Schmeisser, Dieter [Brandenburgische Technische Universitaet, Angewandte Physik-Sensorik, Cottbus (Germany); Weisheit, Martin [GLOBALFOUNDRIES, Dresden (Germany)

    2010-07-01

    The interfacial layers of high dielectric constant (high-k) nanolaminate films are here explored. Problems concerning ALD nanolaminate layers deals mainly with lack of accurate methods to determine in depth profile of few nm thick stacks. Modified angle resolved XPS (ARXPS) and synchrotron radiation XPS(SRXPS) are proposed as methods suitable in layer profiling. Studied stacks containing ZrO/HfO or AlO/ZrO, were prepared on Si substrates by atomic layer deposition (ALD). Two sets of experiments were covered. First dealt with initial growth (up to 20 cycles, with thickness d<2 nm) of AlO/ZrO and included layer by layer insitu investigation by SRXPS. Second experiment refer to industrial grown ZrO/HfO films (d{proportional_to}3 nm) processed with various parameters resulting in both, layer by layer and homogenous depositions. For those samples ex situ XPS, with angle dependent variation of probing depth, measurements were covered. By comparing obtained intensity ratios for different angles with computational developed stack model it was found that no simple layer by layer but some intermixing growth occurred including interaction with silicon substrate.

  17. Photocatalytic C60-amorphous TiO2 composites prepared by atomic layer deposition

    Science.gov (United States)

    Justh, Nóra; Firkala, Tamás; László, Krisztina; Lábár, János; Szilágyi, Imre Miklós

    2017-10-01

    Nanocomposites of TiO2 and single fullerene (C60) molecule are prepared by atomic layer deposition (ALD). To create nucleation sites for the ALD reaction, the bare fullerene is functionalized by H2SO4/HNO3 treatment, which results in C60-SO3H. After a NaOH washing step the intermediate hydrolyzes into C60sbnd OH. This process and the consecutive ALD growth of TiO2 are monitored with FTIR, TG/DTA-MS, EDX, Raman, FTIR, XRD, and TEM measurements. Although the TiO2 grown by ALD at 80 and 160 °C onto fullerol is amorphous it enhances the decomposition of methyl orange under UV exposure. This study proves that amorphous TiO2 grown by low temperature ALD has photocatalytic activity, and it can be used e.g. as self-cleaning coatings also on heat sensitive substrates.

  18. Homogeneous transparent conductive ZnO:Ga by ALD for large LED wafers

    Science.gov (United States)

    Szabó, Zoltán; Baji, Zsófia; Basa, Péter; Czigány, Zsolt; Bársony, István; Wang, Hsin-Ying; Volk, János

    2016-08-01

    Highly conductive and uniform Ga doped ZnO (GZO) films were prepared by atomic layer deposition (ALD) as transparent conductive layers for InGaN/GaN LEDs. The optimal Ga doping concentration was found to be 3 at%. Even for 4" wafers, the TCO layer shows excellent homogeneity of film resistivity (0.8 %) according to Eddy current and spectroscopic ellipsometry mapping. This makes ALD a favourable technique over concurrent methods like MBE and PLD where the up-scaling is problematic. In agreement with previous studies, it was found that by an annealing treatment the quality of the GZO/p-GaN interface can be improved, although it causes the degradation of TCO conductivity. Therefore, a two-step ALD deposition technique was proposed and demonstrated: a "buffer layer" deposited and annealed first was followed by a second deposition step to maintain the high conductivity of the top layer.

  19. Investigation of the initial interface formation between CuInSe2 (112) and ZnO grown by ALD

    Energy Technology Data Exchange (ETDEWEB)

    Janocha, Eike; Pettenkofer, Christian [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Berlin (Germany)

    2011-07-01

    The interface between a solar cell absorber and its transparent conductive oxide (TCO) defines the electrical properties and thus the efficiency of chalcopyrite solar cells. Since large conduction band offsets lower the solar cell photocurrent usually a CdS buffer layer is deposited by chemical bath deposition (CBD) between chalcopyrite absorber and TCO. Due to its toxicity and the interruption of the in-line production process by CBD an alternative buffer layer material would be advantageous. To improve the efficiencies of chalcopyrite solar cells a detailed understanding of the electronic band structure between absorber and TCO is necessary. Therefore, we investigated a model system of a single crystalline CuInSe2 absorber material grown in the technological important (112) orientation by molecular beam epitaxy and an epitaxial ZnO TCO grown layer-by-layer via atomic layer deposition (ALD). ALD is known for being a deposition technique allowing the growth of a single monolayer due to its self-limiting growth characteristics. In situ characterization of the initial growth has been performed after each ZnO deposition step by photoelectron spectroscopies (XPS/UPS/SR-PES) in an UHV growth and analysis system resulting in a detailed view of the interface formation and binding characteristics of the involved elements.

  20. GeSbTe deposition for the PRAM application

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Junghyun [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Choi, Sangjoon [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Lee, Changsoo [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Kang, Yoonho [Nano Fabrication Center, SAIT, Suwon, P.O. Box 111 (Korea, Republic of); Kim, Daeil [School of Materials Science and Engineering. University of Ulsan, San 29, Mugeo-Dong, Nam-Gu, Ulsan 680-749 (Korea, Republic of)]. E-mail: dkim84@mail.ulsan.ac.kr

    2007-02-15

    GeSbTe (GST) chalcogenide thin films for the phase-change random access memory (PRAM) were deposited by an atomic layer deposition (ALD) process. New precursors for GST thin films made with an ALD process were synthesized. Among the synthesized precursors, Ge(N(CH{sub 3}){sub 2}){sub 4}, Sb(N(CH{sub 3}){sub 2}){sub 4}, and Te(i-Pr){sub 2} (i-Pr = iso-propyl) were selected. Using the above precursors, GST thin films were deposited using an H{sub 2} plasma-assisted ALD process. Film resistivity abruptly changed after an N{sub 2} annealing process above a temperature of 350 deg. C. Cross-sectional scanning electron microscope (SEM) photographs of the GST films on the patterned substrate with aspect ratio of 7 shows that the step coverage is about 90%.

  1. Conductive conformal thin film coatings for textured PV: ALD versus sputtering

    Science.gov (United States)

    Dameron, Arrelaine; Christensen, Steven; Galante, Marie; Berry, Joseph; Gillaspie, Dane; Perkins, John; Ginley, David; Gennett, Thomas

    2011-09-01

    Next-generation photovoltaic structures require well-established deposition routes to conformal and conducting materials with defined chemical, physical and electronic composition. This work reports on the preliminary findings associated with conformal metal oxides on structured substrates including: 1) Discovery of sputtering process conditions that can be made semi-conformal when combined with in-situ techniques such as ion-beam milling for honing surface structures; 2) Development of relevant ALD chemistries that are materials-properties competitive with sputtered materials; 3) Evaluation of chemically-functionalized surface structures that maximize surface area but are structurally tailored for efficient gas flow and to minimize line-of-sight shadowing. The initial experiments have centered on combinations of amorphous and crystalline indium oxide, zinc oxide, aluminum zinc oxide, indium tin oxide, fluorinated tin oxide and indium zinc oxide. This presentation will describe these initial experiments and elucidate key physiochemical nature of the deposited thin films.

  2. Very high frequency plasma reactant for atomic layer deposition

    Science.gov (United States)

    Oh, Il-Kwon; Yoo, Gilsang; Yoon, Chang Mo; Kim, Tae Hyung; Yeom, Geun Young; Kim, Kangsik; Lee, Zonghoon; Jung, Hanearl; Lee, Chang Wan; Kim, Hyungjun; Lee, Han-Bo-Ram

    2016-11-01

    Although plasma-enhanced atomic layer deposition (PE-ALD) results in several benefits in the formation of high-k dielectrics, including a low processing temperature and improved film properties compared to conventional thermal ALD, energetic radicals and ions in the plasma cause damage to layer stacks, leading to the deterioration of electrical properties. In this study, the growth characteristics and film properties of PE-ALD Al2O3 were investigated using a very-high-frequency (VHF) plasma reactant. Because VHF plasma features a lower electron temperature and higher plasma density than conventional radio frequency (RF) plasma, it has a larger number of less energetic reaction species, such as radicals and ions. VHF PE-ALD Al2O3 shows superior physical and electrical properties over RF PE-ALD Al2O3, including high growth per cycle, excellent conformality, low roughness, high dielectric constant, low leakage current, and low interface trap density. In addition, interlayer-free Al2O3 on Si was achieved in VHF PE-ALD via a significant reduction in plasma damage. VHF PE-ALD will be an essential process to realize nanoscale devices that require precise control of interfaces and electrical properties.

  3. Plasma-Assisted Atomic Layer Deposition: Basics, Opportunities, and Challenges

    NARCIS (Netherlands)

    Profijt, H. B.; Potts, S. E.; M. C. M. van de Sanden,; Kessels, W. M. M.

    2011-01-01

    Plasma-assisted atomic layer deposition (ALD) is an energy-enhanced method for the synthesis of ultra-thin films with A angstrom-level resolution in which a plasma is employed during one step of the cyclic deposition process. The use of plasma species as reactants allows for more freedom in processi

  4. Plasma-Assisted Atomic Layer Deposition: Basics, Opportunities, and Challenges

    NARCIS (Netherlands)

    Profijt, H. B.; Potts, S. E.; M. C. M. van de Sanden,; Kessels, W. M. M.

    2011-01-01

    Plasma-assisted atomic layer deposition (ALD) is an energy-enhanced method for the synthesis of ultra-thin films with A angstrom-level resolution in which a plasma is employed during one step of the cyclic deposition process. The use of plasma species as reactants allows for more freedom in

  5. Probing initial-stages of ALD growth with dynamic in situ spectroscopic ellipsometry

    Science.gov (United States)

    Muneshwar, Triratna; Cadien, Ken

    2015-02-01

    The initial stages of ALD surface reactions are probed using dynamic in situ spectroscopic ellipsometry (d-iSE) technique during plasma-enhanced ALD of zirconium nitride (ZrN) thin films in spectral range of 0.73-6.4 eV. The measured change in the ellipsometry parameter Δ, with every precursor (TDMAZr) and reactant (forming gas plasma) exposure is interpreted as the combined effect of film growth and change in surface chemistry during ALD. We present application of Bruggeman's effective-medium approximation (B-EMA) in the analysis of d-iSE data to determine fractional surface coverage (θ) of ALD grown film at the end of every deposition cycle. During the deposition of first few ZrN monolayers, d-iSE datasets are analyzed on the basis of surface diffusion enhanced ALD growth, where the surface adsorbed precursor molecules can diffuse over substrate surface to occupy energetically favorable surface sites. The determined surface coverage of ZrN films highlights the effects of substrate enhanced ALD growth.

  6. Mechanistic modeling study on process optimization and precursor utilization with atmospheric spatial atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Zhang; He, Wenjie; Duan, Chenlong [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Chen, Rong, E-mail: rongchen@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Shan, Bin [State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2016-01-15

    Spatial atomic layer deposition (SALD) is a promising technology with the aim of combining the advantages of excellent uniformity and conformity of temporal atomic layer deposition (ALD), and an industrial scalable and continuous process. In this manuscript, an experimental and numerical combined model of atmospheric SALD system is presented. To establish the connection between the process parameters and the growth efficiency, a quantitative model on reactant isolation, throughput, and precursor utilization is performed based on the separation gas flow rate, carrier gas flow rate, and precursor mass fraction. The simulation results based on this model show an inverse relation between the precursor usage and the carrier gas flow rate. With the constant carrier gas flow, the relationship of precursor usage and precursor mass fraction follows monotonic function. The precursor concentration, regardless of gas velocity, is the determinant factor of the minimal residual time. The narrow gap between precursor injecting heads and the substrate surface in general SALD system leads to a low Péclet number. In this situation, the gas diffusion act as a leading role in the precursor transport in the small gap rather than the convection. Fluid kinetics from the numerical model is independent of the specific structure, which is instructive for the SALD geometry design as well as its process optimization.

  7. Vapor-Phase Atomic Layer Deposition of Co9S8 and Its Application for Supercapacitors.

    Science.gov (United States)

    Li, Hao; Gao, Yuanhong; Shao, Youdong; Su, Yantao; Wang, Xinwei

    2015-10-14

    Atomic layer deposition (ALD) of cobalt sulfide (Co9S8) is reported. The deposition process uses bis(N,N'-diisopropylacetamidinato)cobalt(II) and H2S as the reactants and is able to produce high-quality Co9S8 films with an ideal layer-by-layer ALD growth behavior. The Co9S8 films can also be conformally deposited into deep narrow trenches with aspect ratio of 10:1, which demonstrates the high promise of this ALD process for conformally coating Co9S8 on high-aspect-ratio 3D nanostructures. As Co9S8 is a highly promising electrochemical active material for energy devices, we further explore its electrochemical performance by depositing Co9S8 on porous nickel foams for supercapacitor electrodes. Benefited from the merits of ALD for making high-quality uniform thin films, the ALD-prepared electrodes exhibit remarkable electrochemical performance, with high specific capacitance, great rate performance, and long-term cyclibility, which highlights the broad and promising applications of this ALD process for energy-related electrochemical devices, as well as for fabricating complex 3D nanodevices in general.

  8. Controllable ALD synthesis of platinum nanoparticles by tuning different synthesis parameters

    Science.gov (United States)

    Wang, Chuandao; Hu, Linhua; Lin, Yuyuan; Poeppelmeier, Kenneth; Stair, Peter; Marks, Laurence

    2017-10-01

    Pt nanoparticles were successfully deposited using three different atomic layer deposition (ALD) methods, e.g. AB-type, ABC-type and static ABC-type ALD, on two different types of strontium titanate nanocuboids (STO-NCs) samples in a reaction temperature window of 125 °C–300 °C. The influence of reaction temperature, number of ALD cycles, type of substrate, 2nd reagent and type of ALD method on Pt nanoparticle deposition are comprehensively studied and discussed in this work. Varying the reaction temperature and number of cycles across the three different ALD methods affects Pt particle size, density, and loading. Surface termination of STO-NCs substrate will change deposited Pt nanoparticle growth orientation and thermodynamic shape. The B reagent besides platinum precursor can lead to different ligand decomposition mechanism when Pt precursors are exposed: oxygen allows more effective ligand combustion compared to water, however, the Pt particles are more oxidized according to XPS studies. We expect this work provides a way for tailoring nanoparticles with desired size, dispersion, exposed surfaces and chemical state etc, which helps controlling and optimizing their performance when applied as catalysts or nanosensors.

  9. Atomic Layer Deposition from Dissolved Precursors.

    Science.gov (United States)

    Wu, Yanlin; Döhler, Dirk; Barr, Maïssa; Oks, Elina; Wolf, Marc; Santinacci, Lionel; Bachmann, Julien

    2015-10-14

    We establish a novel thin film deposition technique by transferring the principles of atomic layer deposition (ALD) known with gaseous precursors toward precursors dissolved in a liquid. An established ALD reaction behaves similarly when performed from solutions. "Solution ALD" (sALD) can coat deep pores in a conformal manner. sALD offers novel opportunities by overcoming the need for volatile and thermally robust precursors. We establish a MgO sALD procedure based on the hydrolysis of a Grignard reagent.

  10. Atomic layer deposition of perovskite oxides and their epitaxial integration with Si, Ge, and other semiconductors

    Science.gov (United States)

    McDaniel, Martin D.; Ngo, Thong Q.; Hu, Shen; Posadas, Agham; Demkov, Alexander A.; Ekerdt, John G.

    2015-12-01

    Atomic layer deposition (ALD) is a proven technique for the conformal deposition of oxide thin films with nanoscale thickness control. Most successful industrial applications have been with binary oxides, such as Al2O3 and HfO2. However, there has been much effort to deposit ternary oxides, such as perovskites (ABO3), with desirable properties for advanced thin film applications. Distinct challenges are presented by the deposition of multi-component oxides using ALD. This review is intended to highlight the research of the many groups that have deposited perovskite oxides by ALD methods. Several commonalities between the studies are discussed. Special emphasis is put on precursor selection, deposition temperatures, and specific property performance (high-k, ferroelectric, ferromagnetic, etc.). Finally, the monolithic integration of perovskite oxides with semiconductors by ALD is reviewed. High-quality epitaxial growth of oxide thin films has traditionally been limited to physical vapor deposition techniques (e.g., molecular beam epitaxy). However, recent studies have demonstrated that epitaxial oxide thin films may be deposited on semiconductor substrates using ALD. This presents an exciting opportunity to integrate functional perovskite oxides for advanced semiconductor applications in a process that is economical and scalable.

  11. Atomic layer deposition of perovskite oxides and their epitaxial integration with Si, Ge, and other semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    McDaniel, Martin D.; Ngo, Thong Q.; Hu, Shen; Ekerdt, John G., E-mail: ekerdt@utexas.edu [Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Posadas, Agham; Demkov, Alexander A. [Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2015-12-15

    Atomic layer deposition (ALD) is a proven technique for the conformal deposition of oxide thin films with nanoscale thickness control. Most successful industrial applications have been with binary oxides, such as Al{sub 2}O{sub 3} and HfO{sub 2}. However, there has been much effort to deposit ternary oxides, such as perovskites (ABO{sub 3}), with desirable properties for advanced thin film applications. Distinct challenges are presented by the deposition of multi-component oxides using ALD. This review is intended to highlight the research of the many groups that have deposited perovskite oxides by ALD methods. Several commonalities between the studies are discussed. Special emphasis is put on precursor selection, deposition temperatures, and specific property performance (high-k, ferroelectric, ferromagnetic, etc.). Finally, the monolithic integration of perovskite oxides with semiconductors by ALD is reviewed. High-quality epitaxial growth of oxide thin films has traditionally been limited to physical vapor deposition techniques (e.g., molecular beam epitaxy). However, recent studies have demonstrated that epitaxial oxide thin films may be deposited on semiconductor substrates using ALD. This presents an exciting opportunity to integrate functional perovskite oxides for advanced semiconductor applications in a process that is economical and scalable.

  12. Depositing Materials on the Micro- and Nanoscale

    DEFF Research Database (Denmark)

    Mar, Mikkel Dysseholm; Herstrøm, Berit; Shkondin, Evgeniy

    2014-01-01

    on sequential introduction of precursor pulses with intermediate purging steps. The process proceeds by specific surface ligand-exchange reactions and this leads to layer-by-layer growth control. No other thin film deposition technique can approach the conformity achieved by ALD on high aspect ratio structures...

  13. Very high frequency plasma reactant for atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Il-Kwon; Yoo, Gilsang; Yoon, Chang Mo [School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Tae Hyung; Yeom, Geun Young [Department of Advanced Materials Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Kangsik; Lee, Zonghoon [School Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919 (Korea, Republic of); Jung, Hanearl; Lee, Chang Wan [School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Hyungjun, E-mail: hyungjun@yonsei.ac.kr [School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Han-Bo-Ram, E-mail: hbrlee@inu.ac.kr [Department of Materials Science and Engineering, Incheon National University, 406-840 Incheon (Korea, Republic of)

    2016-11-30

    Highlights: • Fundamental research plasma process for thin film deposition is presented. • VHF plasma source for PE-ALD Al{sub 2}O{sub 3} was employed to reduce plasma damage. • The use of VHF plasma improved all of the film qualities and growth characteristics. - Abstract: Although plasma-enhanced atomic layer deposition (PE-ALD) results in several benefits in the formation of high-k dielectrics, including a low processing temperature and improved film properties compared to conventional thermal ALD, energetic radicals and ions in the plasma cause damage to layer stacks, leading to the deterioration of electrical properties. In this study, the growth characteristics and film properties of PE-ALD Al{sub 2}O{sub 3} were investigated using a very-high-frequency (VHF) plasma reactant. Because VHF plasma features a lower electron temperature and higher plasma density than conventional radio frequency (RF) plasma, it has a larger number of less energetic reaction species, such as radicals and ions. VHF PE-ALD Al{sub 2}O{sub 3} shows superior physical and electrical properties over RF PE-ALD Al{sub 2}O{sub 3}, including high growth per cycle, excellent conformality, low roughness, high dielectric constant, low leakage current, and low interface trap density. In addition, interlayer-free Al{sub 2}O{sub 3} on Si was achieved in VHF PE-ALD via a significant reduction in plasma damage. VHF PE-ALD will be an essential process to realize nanoscale devices that require precise control of interfaces and electrical properties.

  14. MOS Ge Diodes Based on High κ Gate Dielectrics Grown by MBE and ALD

    Science.gov (United States)

    Lee, Kun Yu; Lee, W. C.; Lin, T. D.; Lee, C. S.; Chang, Y. C.; Lee, Y. J.; Huang, M. L.; Wu, Y. D.; Hong, M.; Kwo, J.

    2007-03-01

    Germanium-based CMOS technology is gaining importance due to its high carrier mobility. In this work high κ gate-dielectrics, Al2O3, HfO2, Y2O3 and Ga2O3(Gd2O3) grown by MBE and ALD were investigated as passivation layers on n type Ge(100). Thermal stability of the MOS diodes was examined after various anneals. Prior to dielectric depositions surface pretreatments were applied to reduce the unwanted GeOx interfacial layer, and to improve electrical properties. Frequency dispersion of C-V curves was reduced by using a 350^oC preclean process, compared to the sample without precleaning. The leakage current density of ALD grown HfO2 (6.8nm) is 4.6×10-6 A/cm^2 with κ of 10.5. The improved CV curve was attributed to less GeOx formed at substrate and oxide interface, as confirmed by XPS analysis. However, with higher cleaning temperature over 400^oC, the CV curves showed additional inversion capacitance, possibly due to minority carriers from defect states near the interface.

  15. Initial Processes of Atomic Layer Deposition of Al2O3 on InGaAs: Interface Formation Mechanisms and Impact on Metal-Insulator-Semiconductor Device Performance

    Directory of Open Access Journals (Sweden)

    Shinichi Takagi

    2012-03-01

    Full Text Available Interface-formation processes in atomic layer deposition (ALD of Al2O3 on InGaAs surfaces were investigated using on-line Auger electron spectroscopy. Al2O3 ALD was carried out by repeating a cycle of Al(CH33 (trimethylaluminum, TMA adsorption and oxidation by H2O. The first two ALD cycles increased the Al KLL signal, whereas they did not increase the O KLL signal. Al2O3 bulk-film growth started from the third cycle. These observations indicated that the Al2O3/InGaAs interface was formed by reduction of the surface oxides with TMA. In order to investigate the effect of surface-oxide reduction on metal-insulator-semiconductor (MIS properties, capacitors and field-effect transistors (FETs were fabricated by changing the TMA dosage during the interface formation stage. The frequency dispersion of the capacitance-voltage characteristics was reduced by employing a high TMA dosage. The high TMA dosage, however, induced fixed negative charges at the MIS interface and degraded channel mobility.

  16. Influence of surface preparation on atomic layer deposition of Pt films

    Institute of Scientific and Technical Information of China (English)

    Ge Liang; Hu Cheng; Zhu Zhiwei; Zhang Wei; Wu Dongping; Zhang Shili

    2012-01-01

    We report Pt deposition on a Si substrate by means of atomic layer deposition (ALD) using (methylcyclopentadienyl) trimethylplatinum (CH3CsH4Pt(CH3)3) and O2.Silicon substrates with both HF-last and oxidelast surface treatments are employed to investigate the influence of surface preparation on Pt-ALD.A significantlylonger incubation time and less homogeneity are observed for Pt growth on the HF-last substrate compared to the oxide-last substrate.An interfacial oxide layer at the Pt-Si interface is found inevitable even with HF treatment of the Si substrate immediately prior to ALD processing.A plausible explanation to the observed difference of Pt-ALD is discussed.

  17. Interface control of atomic layer deposited oxide coatings by filtered cathodic arc deposited sublayers for improved corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Härkönen, Emma, E-mail: emma.harkonen@helsinki.fi [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland); Tervakangas, Sanna; Kolehmainen, Jukka [DIARC-Technology Inc., Espoo (Finland); Díaz, Belén; Światowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Marcus, Philippe [Laboratoire de Physico-Chimie des Surfaces, CNRS (UMR 7075) – Chimie ParisTech (ENSCP), F-75005 Paris (France); Fenker, Martin [FEM Research Institute, Precious Metals and Metals Chemistry, D-73525 Schwäbisch Gmünd (Germany); Tóth, Lajos; Radnóczi, György [Research Centre for Natural Sciences HAS, (MTA TKK), Budapest (Hungary); Ritala, Mikko [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland)

    2014-10-15

    Sublayers grown with filtered cathodic arc deposition (FCAD) were added under atomic layer deposited (ALD) oxide coatings for interface control and improved corrosion protection of low alloy steel. The FCAD sublayer was either Ta:O or Cr:O–Ta:O nanolaminate, and the ALD layer was Al{sub 2}O{sub 3}–Ta{sub 2}O{sub 5} nanolaminate, Al{sub x}Ta{sub y}O{sub z} mixture or graded mixture. The total thicknesses of the FCAD/ALD duplex coatings were between 65 and 120 nm. Thorough analysis of the coatings was conducted to gain insight into the influence of the FCAD sublayer on the overall coating performance. Similar characteristics as with single FCAD and ALD coatings on steel were found in the morphology and composition of the duplex coatings. However, the FCAD process allowed better control of the interface with the steel by reducing the native oxide and preventing its regrowth during the initial stages of the ALD process. Residual hydrocarbon impurities were buried in the interface between the FCAD layer and steel. This enabled growth of ALD layers with improved electrochemical sealing properties, inhibiting the development of localized corrosion by pitting during immersion in acidic NaCl and enhancing durability in neutral salt spray testing. - Highlights: • Corrosion protection properties of ALD coatings were improved by FCAD sublayers. • The FCAD sublayer enabled control of the coating-substrate interface. • The duplex coatings offered improved sealing properties and durability in NSS. • The protective properties were maintained during immersion in a corrosive solution. • The improvements were due to a more ideal ALD growth on the homogeneous FCAD oxide.

  18. Morphological Characterization of ALD and Doping Effects on Mesoporous SnO2 Aerogels by XPS and Quantitative SEM Image Analysis.

    Science.gov (United States)

    Correa-Baena, Juan-Pablo; Artyushkova, Kateryna; Santoro, Carlo; Atanassov, Plamen; Agrios, Alexander G

    2016-04-20

    Atomic layer deposition (ALD) is unsurpassed in its ability to create thin conformal coatings over very rough and/or porous materials. Yet although the coating thickness on flat surfaces can be measured by ellipsometry, characterization of these coatings on rough surfaces is difficult. Here, two techniques are demonstrated to provide such characterization of ALD-coated TiO2 over mesoporous SnO2 aerogel films on glass substrates, and insights are gained as to the ALD process. First, X-ray photoelectron spectroscopy (XPS) is used to determine the coating thickness over the aerogel, and the results (0.04 nm/cycle) agree well with ellipsometry on flat surfaces up to a coating thickness limit of about 6 nm. Second, quantitative analysis of SEM images of the aerogel cross section is used to determine porosity and roughness, from which coating thickness can be inferred. The analysis reveals increasing porosity from the aerogel/air interface to the aerogel/substrate interface, indicating a thicker ALD coating near the air side, which is consistent with tortuous diffusion through the pores limiting access of ALD precursors to deeper parts of the film. SEM-derived porosity is generally useful in a thin film because bulk methods like nitrogen physisorption or mercury porosimetry are impractical for use with thin-film samples. Therefore, in this study SEM was also used to characterize quantitatively the morphologogical changes in SnO2 aerogel thin films due to doping with Sb. This study can be used as a methodology to understand morphological changes in different types of porous and/or rough materials.

  19. Surface chemistry of the atomic layer deposition of metals and group III oxides

    Science.gov (United States)

    Goldstein, David Nathan

    Atomic Layer Deposition (ALD) is a thin-film growth technique offering precise control of film thickness and the ability to coat high-aspect-ratio features such as trenches and nanopowders. Unlike other film growth techniques, ALD does not require harsh processing conditions and is not limited by line-of-sight deposition. Emerging applications for ALD materials include semiconductor devices, gas sensors, and water-diffusion barriers. The chemistry behind ALD involves understanding how the precursors interact with surfaces to deposit the desired material. All ALD precursors need to be stable on the substrate to ensure self-limiting behavior yet reactive enough to be easily removed with the second reagent. Recent precursor development has provided many volatile organometallic compounds for most of the periodic table. As the number of precursors increases, proper precursor choice becomes crucial. This is because the film properties, growth rates, and growth temperature vary widely between the precursors. Many of the above traits can be predicted with knowledge of the precursor reaction mechanisms. This thesis aims to link surface reaction mechanisms to observed growth and nucleation trends in metal and oxide ALD systems. The first portion of this thesis explores the mechanisms of two ALD oxide systems. First, I examine the mechanism of ALD alumina with ozone. Ozone is used as an oxidant in the semiconductor industry because the deposited Al 2O3 films possess better insulating properties and ozone is easier to purge from a vacuum system. FT-IR analysis reveals a complicated array of surface intermediates such as formate, carbonate, and methoxy groups that form during Al2O3 growth with ozone. Next, a new method to deposit thin films of Ga2O3 is introduced. Gallium oxide is a transparent conducting oxide that needs expensive solid precursors to be deposited by ALD. I show that trimethylgallium is a good high-temperature ALD precursor that deposits films of Ga2O 3 with

  20. Role of Ge and Si substrates in higher-k tetragonal phase formation and interfacial properties in cyclical atomic layer deposition-anneal Hf1-xZrxO2/Al2O3 thin film stacks

    Science.gov (United States)

    Dey, Sonal; Tapily, Kandabara; Consiglio, Steven; Clark, Robert D.; Wajda, Cory S.; Leusink, Gert J.; Woll, Arthur R.; Diebold, Alain C.

    2016-09-01

    Using a five-step atomic layer deposition (ALD)-anneal (DADA) process, with 20 ALD cycles of metalorganic precursors followed by 40 s of rapid thermal annealing at 1073 K, we have developed highly crystalline Hf1-xZrxO2 (0 ≤ x ≤ 1) thin films (DADA ALD process. We surmise that the interfacial metal germanate layer also function as a diffusion barrier limiting excessive Ge uptake into the dielectric film. An ALD Al2O3 passivation layer of thickness ≥1.5 nm is required to minimize Ge diffusion for developing highly conformal and textured HfO2 based higher-k dielectrics on Ge substrates using the DADA ALD process.

  1. Gas Diffusion Barriers Prepared by Spatial Atmospheric Pressure Plasma Enhanced ALD.

    Science.gov (United States)

    Hoffmann, Lukas; Theirich, Detlef; Pack, Sven; Kocak, Firat; Schlamm, Daniel; Hasselmann, Tim; Fahl, Henry; Räupke, André; Gargouri, Hassan; Riedl, Thomas

    2017-02-01

    In this work, we report on aluminum oxide (Al2O3) gas permeation barriers prepared by spatial ALD (SALD) at atmospheric pressure. We compare the growth characteristics and layer properties using trimethylaluminum (TMA) in combination with an Ar/O2 remote atmospheric pressure plasma for different substrate velocities and different temperatures. The resulting Al2O3 films show ultralow water vapor transmission rates (WVTR) on the order of 10(-6) gm(-2)d(-1). In notable contrast, plasma based layers already show good barrier properties at low deposition temperatures (75 °C), while water based processes require a growth temperature above 100 °C to achieve equally low WVTRs. The activation energy for the water permeation mechanism was determined to be 62 kJ/mol.

  2. Surface modification of acetaminophen particles by atomic layer deposition.

    Science.gov (United States)

    Kääriäinen, Tommi O; Kemell, Marianna; Vehkamäki, Marko; Kääriäinen, Marja-Leena; Correia, Alexandra; Santos, Hélder A; Bimbo, Luis M; Hirvonen, Jouni; Hoppu, Pekka; George, Steven M; Cameron, David C; Ritala, Mikko; Leskelä, Markku

    2017-06-15

    Active pharmaceutical ingredients (APIs) are predominantly organic solid powders. Due to their bulk properties many APIs require processing to improve pharmaceutical formulation and manufacturing in the preparation for various drug dosage forms. Improved powder flow and protection of the APIs are often anticipated characteristics in pharmaceutical manufacturing. In this work, we have modified acetaminophen particles with atomic layer deposition (ALD) by conformal nanometer scale coatings in a one-step coating process. According to the results, ALD, utilizing common chemistries for Al2O3, TiO2 and ZnO, is shown to be a promising coating method for solid pharmaceutical powders. Acetaminophen does not undergo degradation during the ALD coating process and maintains its stable polymorphic structure. Acetaminophen with nanometer scale ALD coatings shows slowed drug release. ALD TiO2 coated acetaminophen particles show cytocompatibility whereas those coated with thicker ZnO coatings exhibit the most cytotoxicity among the ALD materials under study when assessed in vitro by their effect on intestinal Caco-2 cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Plasma-Enhanced Atmospheric-Pressure Spatial ALD of Al2O3 and ZrO2

    NARCIS (Netherlands)

    Creyghton, Y.; Illiberi, A.; Mione, M.; Boekel, W. van; Debernardi, N.; Seitz, M.; Bruele, F. van den; Poodt, P.; Roozeboom,F.

    2016-01-01

    Non-thermal plasma sources are known to lower the operation temperatures and widen the process windows in thermal ALD of thin-film materials. In spatial ALD, novel plasma sources with exceptional dimensional and chemical stability are required to provide the flow geometries optimized for efficient t

  4. First principles study of the atomic layer deposition of alumina by TMA-H2O-process.

    Science.gov (United States)

    Weckman, Timo; Laasonen, Kari

    2015-07-14

    Atomic layer deposition (ALD) is a coating technology used to produce highly uniform thin films. Aluminiumoxide, Al2O3, is mainly deposited using trimethylaluminium (TMA) and water as precursors and is the most studied ALD-process to date. However, only few theoretical studies have been reported in the literature. The surface reaction mechanisms and energetics previously reported focus on a gibbsite-like surface model but a more realistic description of the surface can be achieved when the hydroxylation of the surface is taken into account using dissociatively adsorbed water molecules. The adsorbed water changes the structure of the surface and reaction energetics change considerably when compared to previously studied surface model. Here we have studied the TMA-H2O process using density functional theory on a hydroxylated alumina surface and reproduced the previous results for comparison. Mechanisms and energetics during both the TMA and the subsequent water pulse are presented. TMA is found to adsorb exothermically onto the surface. The reaction barriers for the ligand-exchange reactions between the TMA and the surface hydroxyl groups were found to be much lower compared to previously presented results. TMA dissociation on the surface is predicted to saturate at monomethylaluminium. Barriers for proton diffusion between surface sites are observed to be low. TMA adsorption was also found to be cooperative with the formation of methyl bridges between the adsorbants. The water pulse was studied using single water molecules reacting with the DMA and MMA surface species. Barriers for these reactions were found to reasonable in the process conditions. However, stabilizing interactions amongst water molecules were found to lower the reaction barriers and the dynamical nature of water is predicted to be of importance. It is expected that these calculations can only set an upper limit for the barriers during the water pulse.

  5. Spatial atomic layer deposition on flexible porous substrates: ZnO on anodic aluminum oxide films and Al{sub 2}O{sub 3} on Li ion battery electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Kashish [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309 (United States); Routkevitch, Dmitri; Varaksa, Natalia [InRedox, Longmont, Colorado 80544 (United States); George, Steven M., E-mail: Steven.George@Colorado.Edu [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309 and Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309 (United States)

    2016-01-15

    Spatial atomic layer deposition (S-ALD) was examined on flexible porous substrates utilizing a rotating cylinder reactor to perform the S-ALD. S-ALD was first explored on flexible polyethylene terephthalate polymer substrates to obtain S-ALD growth rates on flat surfaces. ZnO ALD with diethylzinc and ozone as the reactants at 50 °C was the model S-ALD system. ZnO S-ALD was then performed on nanoporous flexible anodic aluminum oxide (AAO) films. ZnO S-ALD in porous substrates depends on the pore diameter, pore aspect ratio, and reactant exposure time that define the gas transport. To evaluate these parameters, the Zn coverage profiles in the pores of the AAO films were measured using energy dispersive spectroscopy (EDS). EDS measurements were conducted for different reaction conditions and AAO pore geometries. Substrate speeds and reactant pulse durations were defined by rotating cylinder rates of 10, 100, and 200 revolutions per minute (RPM). AAO pore diameters of 10, 25, 50, and 100 nm were utilized with a pore length of 25 μm. Uniform Zn coverage profiles were obtained at 10 RPM and pore diameters of 100 nm. The Zn coverage was less uniform at higher RPM values and smaller pore diameters. These results indicate that S-ALD into porous substrates is feasible under certain reaction conditions. S-ALD was then performed on porous Li ion battery electrodes to test S-ALD on a technologically important porous substrate. Li{sub 0.20}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} electrodes on flexible metal foil were coated with Al{sub 2}O{sub 3} using 2–5 Al{sub 2}O{sub 3} ALD cycles. The Al{sub 2}O{sub 3} ALD was performed in the S-ALD reactor at a rotating cylinder rate of 10 RPM using trimethylaluminum and ozone as the reactants at 50 °C. The capacity of the electrodes was then tested versus number of charge–discharge cycles. These measurements revealed that the Al{sub 2}O{sub 3} S-ALD coating on the electrodes enhanced the capacity stability. This S-ALD

  6. Electrochemical atomic layer deposition of copper nanofilms on ruthenium

    Science.gov (United States)

    Gebregziabiher, Daniel K.; Kim, Youn-Geun; Thambidurai, Chandru; Ivanova, Valentina; Haumesser, Paul-Henri; Stickney, John L.

    2010-04-01

    As ULSI scales to smaller and smaller dimensions, it has become necessary to form layers of materials only a few nm thick. In addition, trenches are now being incorporated in ULSI formation which require conformal coating and will not be amenable to CMP. Atomic layer deposition (ALD) is being developed to address such issues. ALD is the formation of materials layer by layer using self-limiting reactions. This article describes the formation of Cu seed layers (for the Cu damascene process) on a Ru barrier layer. The deposit was formed by the electrochemical analog of ALD, using electrochemical self-limiting reactions which are referred to as underpotential deposition (UPD). Monolayer restricted galvanic displacement was used to form atomic layers of Cu. First Pb UPD was deposited, forming a sacrificial layer, and then a Cu +2 solution was flushed into the cell and Pb was exchanged for Cu. A linear dependence was shown for Cu growth over 8 ALD cycles, and STM showed a conformal deposition, as expected for an ALD process. Relative Cu coverages were determined using Auger electron spectroscopy, while absolute Cu coverages were obtained from coulometry during oxidative stripping of the deposits. Use of a Cl - containing electrolyte results in Cu deposits covered with an atomic layer of Cl atoms, which have been shown to protect the surfaced from oxidation during various stages of the deposition process. The 10 nm thick Ru substrates were formed on Si(1 0 0) wafers, and were partially oxidized upon receipt. Electrochemical reduction, prior to Cu deposition, removed the oxygen and some traces of carbon, the result of transport. Ion bombardment proved to clean all oxygen and carbon traces from the surface.

  7. Organic and inorganic–organic thin film structures by molecular layer deposition: A review

    Directory of Open Access Journals (Sweden)

    Pia Sundberg

    2014-07-01

    Full Text Available The possibility to deposit purely organic and hybrid inorganic–organic materials in a way parallel to the state-of-the-art gas-phase deposition method of inorganic thin films, i.e., atomic layer deposition (ALD, is currently experiencing a strongly growing interest. Like ALD in case of the inorganics, the emerging molecular layer deposition (MLD technique for organic constituents can be employed to fabricate high-quality thin films and coatings with thickness and composition control on the molecular scale, even on complex three-dimensional structures. Moreover, by combining the two techniques, ALD and MLD, fundamentally new types of inorganic–organic hybrid materials can be produced. In this review article, we first describe the basic concepts regarding the MLD and ALD/MLD processes, followed by a comprehensive review of the various precursors and precursor pairs so far employed in these processes. Finally, we discuss the first proof-of-concept experiments in which the newly developed MLD and ALD/MLD processes are exploited to fabricate novel multilayer and nanostructure architectures by combining different inorganic, organic and hybrid material layers into on-demand designed mixtures, superlattices and nanolaminates, and employing new innovative nanotemplates or post-deposition treatments to, e.g., selectively decompose parts of the structure. Such layer-engineered and/or nanostructured hybrid materials with exciting combinations of functional properties hold great promise for high-end technological applications.

  8. Area-Selective Atomic Layer Deposition: Conformal Coating, Subnanometer Thickness Control, and Smart Positioning.

    Science.gov (United States)

    Fang, Ming; Ho, Johnny C

    2015-09-22

    Transistors have already been made three-dimensional (3D), with device channels (i.e., fins in trigate field-effect transistor (FinFET) technology) that are taller, thinner, and closer together in order to enhance device performance and lower active power consumption. As device scaling continues, these transistors will require more advanced, fabrication-enabling technologies for the conformal deposition of high-κ dielectric layers on their 3D channels with accurate position alignment and thickness control down to the subnanometer scale. Among many competing techniques, area-selective atomic layer deposition (AS-ALD) is a promising method that is well suited to the requirements without the use of complicated, complementary metal-oxide semiconductor (CMOS)-incompatible processes. However, further progress is limited by poor area selectivity for thicker films formed via a higher number of ALD cycles as well as the prolonged processing time. In this issue of ACS Nano, Professor Stacy Bent and her research group demonstrate a straightforward self-correcting ALD approach, combining selective deposition with a postprocess mild chemical etching, which enables selective deposition of dielectric films with thicknesses and processing times at least 10 times larger and 48 times shorter, respectively, than those obtained by conventional AS-ALD processes. These advances present an important technological breakthrough that may drive the AS-ALD technique a step closer toward industrial applications in electronics, catalysis, and photonics, etc. where more efficient device fabrication processes are needed.

  9. Thermal and plasma-enhanced oxidation of ALD TiN

    NARCIS (Netherlands)

    Groenland, A.W.; Brunets, I.; Boogaard, A.; Aarnink, A.A.I.; Kovalgin, A.Y.; Schmitz, J.

    2008-01-01

    Despite its high chemical stability, sputtered stoichiometric TiN can still be oxidized at temperatures below 400 ºC, whereas a non-stoichiometric TiN is known to oxidize even at room temperature. In this work, the oxidation behaviour of thin TiN layers, realized via atomic layer deposition (ALD), i

  10. Self-limiting atomic layer deposition of conformal nanostructured silver films

    Science.gov (United States)

    Golrokhi, Zahra; Chalker, Sophia; Sutcliffe, Christopher J.; Potter, Richard J.

    2016-02-01

    The controlled deposition of ultra-thin conformal silver nanoparticle films is of interest for applications including anti-microbial surfaces, plasmonics, catalysts and sensors. While numerous techniques can produce silver nanoparticles, few are able to produce highly conformal coatings on high aspect ratio surfaces, together with sub-nanometre control and scalability. Here we develop a self-limiting atomic layer deposition (ALD) process for the deposition of conformal metallic silver nanoparticle films. The films have been deposited using direct liquid injection ALD with ((hexafluoroacetylacetonato)silver(I)(1,5-cyclooctadiene)) and propan-1-ol. An ALD temperature window between 123 and 128 °C is identified and within this range self-limiting growth is confirmed with a mass deposition rate of ∼17.5 ng/cm2/cycle. The effects of temperature, precursor dose, co-reactant dose and cycle number on the deposition rate and on the properties of the films have been systematically investigated. Under self-limiting conditions, films are metallic silver with a nano-textured surface topography and nanoparticle size is dependent on the number of ALD cycles. The ALD reaction mechanisms have been elucidated using in-situ quartz crystal microbalance (QCM) measurements, showing chemisorption of the silver precursor, followed by heterogeneous catalytic dehydrogenation of the alcohol to form metallic silver and an aldehyde.

  11. Antireflection coatings on plastics deposited by plasma polymerization process

    Indian Academy of Sciences (India)

    K M K Srivatsa; M Bera; A Basu; T K Bhattacharya

    2008-08-01

    Antireflection coatings (ARCs) are deposited on the surfaces of optical elements like spectacle lenses to increase light transmission and improve their performance. In the ophthalmic industry, plastic lenses are rapidly displacing glass lenses due to several advantageous features. However, the deposition of ARCs on plastic lenses is a challenging task, because the plastic surface needs treatment for adhesion improvement and surface hardening before depositing the ARC. This surface treatment is usually done in a multi-stage process—exposure to energetic radiations, followed by deposition of a carbonyl hard coating by spin or dip coating processes, UV curing, etc. However, this treatment can also be done by plasma processes. Moreover, the plasma polymerization process allows deposition of optical films at room temperature, essential for plastics. The energetic ions in plasma processes provide similar effects as in ion assisted physical deposition processes to produce hard coatings, without requiring sophisticated ion sources. The plasma polymerization process is more economical than ion-assisted physical vapour deposition processes as regards equipment and source materials and is more cost-effective, enabling the surface treatment and deposition of the ARC in the same deposition system in a single run by varying the system parameters at each step. Since published results of the plasma polymerization processes developed abroad are rather sketchy and the techniques are mostly veiled in commercial secrecy, innovative and indigenous plasma-based techniques have been developed in this work for depositing the complete ARCs on plastic substrates.

  12. The Antibacterial Polyamide 6-ZnO Hierarchical Nanofibers Fabricated by Atomic Layer Deposition and Hydrothermal Growth

    Science.gov (United States)

    Wang, Zhengduo; Zhang, Li; Liu, Zhongwei; Sang, Lijun; Yang, Lizhen; Chen, Qiang

    2017-06-01

    In this paper, we report the combination of atomic layer deposition (ALD) with hydrothermal techniques to deposit ZnO on electrospun polyamide 6 (PA 6) nanofiber (NF) surface in the purpose of antibacterial application. The micro- and nanostructures of the hierarchical fibers are characterized by field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM), and scanning transmission electron microscopy (STEM). We find that NFs can grow into "water lily"- and "caterpillar"-like shapes, which depend on the number of ALD cycles and the hydrothermal reaction period. It is believed that the thickness of ZnO seed layer by ALD process and the period in hydrothermal reaction have the same importance in crystalline growth and hierarchical fiber formation. The tests of antibacterial activity demonstrate that the ZnO/PA 6 core-shell composite fabricated by the combination of ALD with hydrothermal are markedly efficient in suppressing bacteria survivorship.

  13. Temperature-dependent magnetic properties of Ni nanotubes synthesized by atomic layer deposition

    Science.gov (United States)

    Pereira, Alejandro; Palma, Juan L.; Denardin, Juliano C.; Escrig, Juan

    2016-08-01

    Highly-ordered and conformal Ni nanotube arrays were prepared by combining atomic layer deposition (ALD) in a porous alumina matrix with a subsequent thermal reduction process. In order to obtain NiO tubes, one ALD NiCp2/O3 cycle was repeated 2000 times. After the ALD process, the sample is reduced from NiO to metallic Ni under hydrogen atmosphere. Their magnetic properties such as coercivity and squareness have been determined in a vibrating sample magnetometer in the temperature range from 5-300 K for applied magnetic fields parallel and perpendicular to the nanotube axis. Ni nanotubes synthesized by ALD provide a promising opportunity for potential applications in spintronics, data storage and bio-applications.

  14. Near room-temperature direct encapsulation of organic photovoltaics by plasma-based deposition techniques

    Science.gov (United States)

    Perrotta, Alberto; Fuentes-Hernandez, Canek; Khan, Talha M.; Kippelen, Bernard; Creatore, Mariadriana; Graham, Samuel

    2017-01-01

    Plasma-assisted atomic layer deposition (ALD) is used for the deposition of environmental barriers directly onto organic photovoltaic devices (OPVs) at near room temperature (30 °C). To study the effect of the ALD process on the organic materials forming the device, the precursor diffusion and intermixing at the interface during the growth of different plasma-assisted ALD inorganic barriers (i.e. Al2O3 and TiO2) onto the organic photoactive layer (P3HT:ICBA) was investigated. Depth profile x-ray photoelectron spectroscopy was used to analyze the composition of the organic/inorganic interface to investigate the infiltration of the plasma-assisted ALD precursors into the photoactive layer as a function of the precursor dimension, the process temperature, and organic layer morphology. The free volume in the photoactive layer accessible to the ALD precursor was characterized by means of ellipsometric porosimetry (EP) and spectroscopic ellipsometry as a function of temperature. The organic layer is shown to exhibit free volume broadening at high temperatures, increasing the infiltration depth of the ALD precursor into the photoactive layer. Furthermore, based on previous investigations, the intrinsic permeation properties of the inorganic layers deposited by plasma-assisted ALD were predicted from the nano-porosity content as measured by EP and found to be in the 10-6 gm-2 d-1 range. Insight from our studies was used to design and fabricate multilayer barriers synthesized at near-room temperature by plasma-assisted ALD in combination with plasma-enhanced CVD onto organic photovoltaic (OPVs) devices. Encapsulated OPVs displayed shelf-lifetimes up to 1400 h at ambient conditions.

  15. ALD Functionalized Nanoporous Gold: Thermal Stability, Mechanical Properties, and Catalytic Activity

    Energy Technology Data Exchange (ETDEWEB)

    Biener, M M; Biener, J; Wichmann, A; Wittstock, A; Baumann, T F; Baeumer, M; Hamza, A V

    2011-03-24

    Nanoporous metals have many technologically promising applications but their tendency to coarsen limits their long-term stability and excludes high temperature applications. Here, we demonstrate that atomic layer deposition (ALD) can be used to stabilize and functionalize nanoporous metals. Specifically, we studied the effect of nanometer-thick alumina and titania ALD films on thermal stability, mechanical properties, and catalytic activity of nanoporous gold (np-Au). Our results demonstrate that even only one-nm-thick oxide films can stabilize the nanoscale morphology of np-Au up to 1000 C, while simultaneously making the material stronger and stiffer. The catalytic activity of np-Au can be drastically increased by TiO{sub 2} ALD coatings. Our results open the door to high temperature sensor, actuator, and catalysis applications and functionalized electrodes for energy storage and harvesting applications.

  16. Room temperature plasma enhanced atomic layer deposition for TiO{sub 2} and WO{sub 3} films

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, Alexander; Schnabel, Hans-Dieter, E-mail: Hans.Dieter.Schnabel@fh-zwickau.de; Reinhold, Ullrich; Rauer, Sebastian; Neidhardt, Andreas [Department of Physical Engineering and Informatics, University of Applied Science, Westsächsische Hochschule Zwickau, Dr.-Friedrichs-Ring 2a, 08056 Zwíckau (Germany)

    2016-01-15

    This paper presents a study on plasma enhanced atomic layer deposition (ALD) of TiO{sub 2} and WO{sub 3} films on silicon substrates. At low temperatures, ALD processes, which are not feasible at high temperatures, could be possible. For example, temperatures at 180 °C and above allow no WO{sub 3} ALD process with WF{sub 6} as a precursor because etching processes hinder film growth. Further low temperature deposition techniques are needed to coat temperature sensitive materials. For the deposition, WF{sub 6} and TiCl{sub 4} are used as metal precursors and O{sub 2} and H{sub 2}O as oxygen sources. The depositions were accomplished in the temperature range of 30 °C up to 180 °C for both metal oxides. Spectroscopic ellipsometry, x-ray reflection, and grazing incidence diffraction were used to investigate the deposited ALD thin films. Film growth, density, crystallinity, and roughness are discussed as functions of temperature after ensuring the ALD requirement of self-saturating adsorption. Growth rates and measured material properties are in good agreement with literature data.

  17. Low-temperature SiON films deposited by plasma-enhanced atomic layer deposition method using activated silicon precursor

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Sungin; Kim, Jun-Rae; Kim, Seongkyung; Hwang, Cheol Seong; Kim, Hyeong Joon, E-mail: thinfilm@snu.ac.kr [Department of Materials Science and Engineering with Inter-University Semiconductor Research Center (ISRC), Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of); Ryu, Seung Wook, E-mail: tazryu78@gmail.com [Department of Electrical Engineering, Stanford University, Stanford, California 94305-2311 (United States); Cho, Seongjae [Department of Electronic Engineering and New Technology Component & Material Research Center (NCMRC), Gachon University, Seongnam-si, Gyeonggi-do 13120 (Korea, Republic of)

    2016-01-15

    It has not been an easy task to deposit SiN at low temperature by conventional plasma-enhanced atomic layer deposition (PE-ALD) since Si organic precursors generally have high activation energy for adsorption of the Si atoms on the Si-N networks. In this work, in order to achieve successful deposition of SiN film at low temperature, the plasma processing steps in the PE-ALD have been modified for easier activation of Si precursors. In this modification, the efficiency of chemisorption of Si precursor has been improved by additional plasma steps after purging of the Si precursor. As the result, the SiN films prepared by the modified PE-ALD processes demonstrated higher purity of Si and N atoms with unwanted impurities such as C and O having below 10 at. % and Si-rich films could be formed consequently. Also, a very high step coverage ratio of 97% was obtained. Furthermore, the process-optimized SiN film showed a permissible charge-trapping capability with a wide memory window of 3.1 V when a capacitor structure was fabricated and measured with an insertion of the SiN film as the charge-trap layer. The modified PE-ALD process using the activated Si precursor would be one of the most practical and promising solutions for SiN deposition with lower thermal budget and higher cost-effectiveness.

  18. Substrate Biasing during Plasma-Assisted ALD for Crystalline Phase-Control of TiO(2) Thin Films

    NARCIS (Netherlands)

    Profijt, H. B.; M. C. M. van de Sanden,; Kessels, W. M. M.

    2012-01-01

    Substrate biasing has been implemented in a remote plasma atomic layer deposition (ALD) reactor, enabling control of the ion energy up to 260 eV. For TiO(2) films deposited from Ti(Cp(Me))(NMe(2))(3) and O(2) plasma it is demonstrated that the crystalline phase can be tailored by tuning the ion ener

  19. Interface Energy Alignment of Atomic-Layer-Deposited VOx on Pentacene: an in Situ Photoelectron Spectroscopy Investigation.

    Science.gov (United States)

    Zhao, Ran; Gao, Yuanhong; Guo, Zheng; Su, Yantao; Wang, Xinwei

    2017-01-18

    Ultrathin atomic-layer-deposited (ALD) vanadium oxide (VOx) interlayer has recently been demonstrated for remarkably reducing the contact resistance in organic electronic devices (Adv. Funct. Mater. 2016, 26, 4456). Herein, we present an in situ photoelectron spectroscopy investigation (including X-ray and ultraviolet photoelectron spectroscopies) of ALD VOx grown on pentacene to understand the role of the ALD VOx interlayer for the improved contact resistance. The in situ photoelectron spectroscopy characterizations allow us to monitor the ALD growth process of VOx and trace the evolutions of the work function, pentacene HOMO level, and VOx defect states during the growth. The initial VOx growth is found to be partially delayed on pentacene in the first ∼20 ALD cycles. The underneath pentacene layer is largely intact after ALD. The ALD VOx is found to contain a high density of defect states starting from 0.67 eV below the Fermi level, and the energy level of these defect states is in excellent alignment with the HOMO level of pentacene, which therefore allows these VOx defect states to provide an efficient hole-injection pathway at the contact interface.

  20. Barrier properties of plastic films coated with an Al{sub 2}O{sub 3} layer by roll-to-toll atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hirvikorpi, Terhi, E-mail: Terhi.Hirvikorpi@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Laine, Risto, E-mail: Risto.Laine@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Vähä-Nissi, Mika, E-mail: Mika.Vaha-Nissi@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Kilpi, Väinö, E-mail: Vaino.Kilpi@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Salo, Erkki, E-mail: Erkki.Salo@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Li, Wei-Min, E-mail: Wei-Min.Li@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Lindfors, Sven, E-mail: Sven.Lindfors@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Vartiainen, Jari, E-mail: Jari.Vartiainen@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Kenttä, Eija, E-mail: Eija.Kentta@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Nikkola, Juha, E-mail: Juha.Nikkola@vtt.fi [VTT Technical Research Centre of Finland, P.O. Box 1300, FI-33101 Tampere (Finland); Harlin, Ali, E-mail: Ali.Harlin@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Kostamo, Juhana, E-mail: Juhana.Kostamo@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland)

    2014-01-01

    Thin (30–40 nm) and highly uniform Al{sub 2}O{sub 3} coatings have been deposited at relatively low temperature of 100 °C onto various polymeric materials employing the atomic layer deposition (ALD) technique, both batch and roll-to-roll (R2R) mode. The applications for ALD have long been limited those feasible for batch processing. The work demonstrates that R2R ALD can deposit thin films with properties that are comparable to the film properties fabricated by in batch. This accelerates considerably the commercialization of many products, such as flexible, printed electronics, organic light-emitting diode lighting, third generation thin film photovoltaic devices, high energy density thin film batteries, smart textiles, organic sensors, organic/recyclable packaging materials, and flexible displays, to name a few. - Highlights: • Thin and uniform Al{sub 2}O{sub 3} coatings have been deposited onto polymers materials. • Batch and roll-to-roll (R2R) atomic layer deposition (ALD) have been employed. • Deposition with either process improved the barrier properties. • Sensitivity of coated films to defects affects barrier obtained with R2R ALD.

  1. Atomic layer deposition of HfO{sub 2} onto SiO{sub 2} substrates investigated in-situ by non-contact UHV/AFM

    Energy Technology Data Exchange (ETDEWEB)

    Kolanek, Krzysztof; Karavaev, Konstantin; Tallarida, Massimo; Schmeisser, Dieter [Brandenburgische Technische Universitaet, LS Angewandte Physik-Sensorik, Cottbus (Germany)

    2010-07-01

    We investigated in-situ the atomic layer deposition (ALD) of HfO{sub 2} onto SiO{sub 2} substrates with ultra high vacuum (UHV) non-contact atomic force microscope (NC-AFM). The ALD process was started after detailed analysis of the initial Si(001)/SiO{sub 2} substrate. The ALD cycles, made by using tetrakis-di-methyl-amido-Hf (TDMAHf) and water as precursors, were performed on the SiO{sub 2} substrate maintained at 230 C. We studied the relation between the film growth and the root mean square surface roughness, surface skewness, kurtosis, fractal dimension and correlation length. In the initial stages of the ALD process with our analysis of the surface height histograms we were capable of determination: HfO{sub 2} layer thickness, surface coverage and surface roughness of a substrate and deposited material. Observation of the surface height histograms evolution during deposition allowed us to verify conformal and effective ALD growth on SiO{sub 2} substrate. With this detailed analysis of the surface topography we confirmed the completion of the first HfO{sub 2} layer after four ALD cycles.

  2. Fully ALD-grown TiN/Hf0.5Zr0.5O2/TiN stacks: Ferroelectric and structural properties

    Science.gov (United States)

    Zarubin, Sergei; Suvorova, Elena; Spiridonov, Maksim; Negrov, Dmitrii; Chernikova, Anna; Markeev, Andrey; Zenkevich, Andrei

    2016-11-01

    Since the discovery of ferroelectricity (FE) in HfO2-based thin films, they are gaining increasing attention as a viable alternative to conventional FE in the next generation of non-volatile memory devices. In order to further increase the density of elements in the integrated circuits, it is essential to adopt a three-dimensional design. Since atomic layer deposition (ALD) processes are extremely conformal, ALD is the favored approach in the production of 3D ferroelectric random access memory. Here, we report the fabrication of fully ALD-grown capacitors comprising a 10-nm-thick FE Hf0.5Zr0.5O2 layer sandwiched between TiN electrodes, which are subjected to a detailed investigation of the structural and functional properties. The robust FE properties of Hf0.5Zr0.5O2 films in capacitors are established by several alternative techniques. We demonstrate a good scalability of TiN/Hf0.5Zr0.5O2/TiN FE capacitors down to 100-nm size and the polarization retention in the test "one transistor-one capacitor" (1T-1C) cells after 1010 writing cycles. The presence of a non-centrosymmetric orthorhombic phase responsible for FE properties in the alloyed polycrystalline Hf0.5Zr0.5O2 films is established by transmission electron microscopy. Given the ability of the ALD technique to grow highly conformal films and multilayered structures, the obtained results indicate the route for the design of FE non-volatile memory devices in 3D integrated circuits.

  3. Thin films of copper oxide and copper grown by atomic layer deposition for applications in metallization systems of microelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Waechtler, Thomas

    2010-05-25

    Copper-based multi-level metallization systems in today's ultralarge-scale integrated electronic circuits require the fabrication of diffusion barriers and conductive seed layers for the electrochemical metal deposition. Such films of only several nanometers in thickness have to be deposited void-free and conformal in patterned dielectrics. The envisaged further reduction of the geometric dimensions of the interconnect system calls for coating techniques that circumvent the drawbacks of the well-established physical vapor deposition. The atomic layer deposition method (ALD) allows depositing films on the nanometer scale conformally both on three-dimensional objects as well as on large-area substrates. The present work therefore is concerned with the development of an ALD process to grow copper oxide films based on the metal-organic precursor bis(trin- butylphosphane)copper(I)acetylacetonate [({sup n}Bu{sub 3}P){sub 2}Cu(acac)]. This liquid, non-fluorinated {beta}-diketonate is brought to react with a mixture of water vapor and oxygen at temperatures from 100 to 160 C. Typical ALD-like growth behavior arises between 100 and 130 C, depending on the respective substrate used. On tantalum nitride and silicon dioxide substrates, smooth films and selfsaturating film growth, typical for ALD, are obtained. On ruthenium substrates, positive deposition results are obtained as well. However, a considerable intermixing of the ALD copper oxide with the underlying films takes place. Tantalum substrates lead to a fast self-decomposition of the copper precursor. As a consequence, isolated nuclei or larger particles are always obtained together with continuous films. The copper oxide films grown by ALD can be reduced to copper by vapor-phase processes. If formic acid is used as the reducing agent, these processes can already be carried out at similar temperatures as the ALD, so that agglomeration of the films is largely avoided. Also for an integration with subsequent

  4. A comparative study on electrical characteristics of crystalline AlN thin films deposited by ICP and HCPA-sourced atomic layer deposition

    Science.gov (United States)

    Altuntas, Halit; Bayrak, Turkan

    2017-03-01

    In this work, we aimed to investigate the effects of two different plasma sources on the electrical properties of low-temperature plasma-assisted atomic layer deposited (PA-ALD) AlN thin films. To compare the electrical properties, 50 nm thick AlN films were grown on p-type Si substrates at 200 °C by using an inductively coupled RF-plasma (ICP) and a stainless steel hollow cathode plasma-assisted (HCPA) ALD systems. Al/AlN/ p-Si metal-insulator-semiconductor (MIS) capacitor devices were fabricated and capacitance versus voltage ( C- V) and current-voltage ( I- V) measurements performed to assess the basic important electrical parameters such as dielectric constant, effective charge density, flat-band voltage, breakdown field, and threshold voltage. In addition, structural properties of the films were presented and compared. The results show that although HCPA-ALD deposited AlN thin films has structurally better and has a lower effective charge density ( N eff ) value than ICP-ALD deposited AlN films, those films have large leakage current, low dielectric constant, and low breakdown field. This situation was attributed to the involvement of Si atoms into the AlN layers during the HCPA-ALD processing leads to additional current path at AlN/Si interface and might impair the electrical properties.

  5. A comparative study on electrical characteristics of crystalline AlN thin films deposited by ICP and HCPA-sourced atomic layer deposition

    Science.gov (United States)

    Altuntas, Halit; Bayrak, Turkan

    2016-12-01

    In this work, we aimed to investigate the effects of two different plasma sources on the electrical properties of low-temperature plasma-assisted atomic layer deposited (PA-ALD) AlN thin films. To compare the electrical properties, 50 nm thick AlN films were grown on p-type Si substrates at 200 °C by using an inductively coupled RF-plasma (ICP) and a stainless steel hollow cathode plasma-assisted (HCPA) ALD systems. Al/AlN/p-Si metal-insulator-semiconductor (MIS) capacitor devices were fabricated and capacitance versus voltage (C-V) and current-voltage (I-V) measurements performed to assess the basic important electrical parameters such as dielectric constant, effective charge density, flat-band voltage, breakdown field, and threshold voltage. In addition, structural properties of the films were presented and compared. The results show that although HCPA-ALD deposited AlN thin films has structurally better and has a lower effective charge density (N eff ) value than ICP-ALD deposited AlN films, those films have large leakage current, low dielectric constant, and low breakdown field. This situation was attributed to the involvement of Si atoms into the AlN layers during the HCPA-ALD processing leads to additional current path at AlN/Si interface and might impair the electrical properties.

  6. Synthesis and deposition of metal nanoparticles by gas condensation process

    Energy Technology Data Exchange (ETDEWEB)

    Maicu, Marina, E-mail: marina.maicu@fep.fraunhofer.de; Glöß, Daniel; Frach, Peter [Fraunhofer Institut für Elektronenstrahl und Plasmatechnik, FEP, Winterbergstraße 28, 01277 Dresden (Germany); Schmittgens, Ralph; Gerlach, Gerald [Institut für Festkörperelektronik, IFE, TU Dresden, Helmholtz Straße 18, 01069 Dresden (Germany); Hecker, Dominic [Fraunhofer Institut für Elektronenstrahl und Plasmatechnik, FEP, Winterbergstraße 28, 01277 Dresden, Germany and Institut für Festkörperelektronik, IFE, TU Dresden, Helmholtz Straße 18, 01069 Dresden (Germany)

    2014-03-15

    In this work, the synthesis of Pt and Ag nanoparticles by means of the inert gas phase condensation of sputtered atomic vapor is presented. The process parameters (power, sputtering time, and gas flow) were varied in order to study the relationship between deposition conditions and properties of the nanoparticles such as their quantity, size, and size distribution. Moreover, the gas phase condensation process can be combined with a plasma enhanced chemical vapor deposition procedure in order to deposit nanocomposite coatings consisting of metallic nanoparticles embedded in a thin film matrix material. Selected examples of application of the generated nanoparticles and nanocomposites are discussed.

  7. Energy Deposition Processes in Titan's Upper Atmosphere

    Science.gov (United States)

    Sittler, Edward C., Jr.; Bertucci, Cesar; Coates, Andrew; Cravens, Tom; Dandouras, Iannis; Shemansky, Don

    2008-01-01

    Most of Titan's atmospheric organic and nitrogen chemistry, aerosol formation, and atmospheric loss are driven from external energy sources such as Solar UV, Saturn's magnetosphere, solar wind and galactic cosmic rays. The Solar UV tends to dominate the energy input at lower altitudes of approximately 1100 km but which can extend down to approximately 400 km, while the plasma interaction from Saturn's magnetosphere, Saturn's magnetosheath or solar wind are more important at higher altitudes of approximately 1400 km, but the heavy ion plasma [O(+)] of approximately 2 keV and energetic ions [H(+)] of approximately 30 keV or higher from Saturn's magnetosphere can penetrate below 950km. Cosmic rays with energies of greater than 1 GeV can penetrate much deeper into Titan's atmosphere with most of its energy deposited at approximately 100 km altitude. The haze layer tends to dominate between 100 km and 300 km. The induced magnetic field from Titan's interaction with the external plasma can be very complex and will tend to channel the flow of energy into Titan's upper atmosphere. Cassini observations combined with advanced hybrid simulations of the plasma interaction with Titan's upper atmosphere show significant changes in the character of the interaction with Saturn local time at Titan's orbit where the magnetosphere displays large and systematic changes with local time. The external solar wind can also drive sub-storms within the magnetosphere which can then modify the magnetospheric interaction with Titan. Another important parameter is solar zenith angle (SZA) with respect to the co-rotation direction of the magnetospheric flow. Titan's interaction can contribute to atmospheric loss via pickup ion loss, scavenging of Titan's ionospheric plasma, loss of ionospheric plasma down its induced magnetotail via an ionospheric wind, and non-thermal loss of the atmosphere via heating and sputtering induced by the bombardment of magnetospheric keV ions and electrons. This

  8. Energy Deposition Processes in Titan's Upper Atmosphere

    Science.gov (United States)

    Sittler, Edward C., Jr.; Bertucci, Cesar; Coates, Andrew; Cravens, Tom; Dandouras, Iannis; Shemansky, Don

    2008-01-01

    Most of Titan's atmospheric organic and nitrogen chemistry, aerosol formation, and atmospheric loss are driven from external energy sources such as Solar UV, Saturn's magnetosphere, solar wind and galactic cosmic rays. The Solar UV tends to dominate the energy input at lower altitudes of approximately 1100 km but which can extend down to approximately 400 km, while the plasma interaction from Saturn's magnetosphere, Saturn's magnetosheath or solar wind are more important at higher altitudes of approximately 1400 km, but the heavy ion plasma [O(+)] of approximately 2 keV and energetic ions [H(+)] of approximately 30 keV or higher from Saturn's magnetosphere can penetrate below 950km. Cosmic rays with energies of greater than 1 GeV can penetrate much deeper into Titan's atmosphere with most of its energy deposited at approximately 100 km altitude. The haze layer tends to dominate between 100 km and 300 km. The induced magnetic field from Titan's interaction with the external plasma can be very complex and will tend to channel the flow of energy into Titan's upper atmosphere. Cassini observations combined with advanced hybrid simulations of the plasma interaction with Titan's upper atmosphere show significant changes in the character of the interaction with Saturn local time at Titan's orbit where the magnetosphere displays large and systematic changes with local time. The external solar wind can also drive sub-storms within the magnetosphere which can then modify the magnetospheric interaction with Titan. Another important parameter is solar zenith angle (SZA) with respect to the co-rotation direction of the magnetospheric flow. Titan's interaction can contribute to atmospheric loss via pickup ion loss, scavenging of Titan's ionospheric plasma, loss of ionospheric plasma down its induced magnetotail via an ionospheric wind, and non-thermal loss of the atmosphere via heating and sputtering induced by the bombardment of magnetospheric keV ions and electrons. This

  9. The activity of ALD-prepared PtCo catalysts for ethanol oxidation in alkaline media

    OpenAIRE

    Santasalo-Aarnio, Annukka; Sairanen, Emma; Arán-Ais, Rosa M.; Figueiredo, Marta C.; Hua, Jiang; Feliu, Juan M.; Lehtonen, Juha; Karinen, Reetta; Kallio, Tanja

    2014-01-01

    Controlled bimetallic catalyst materials can be obtained using atomic layer deposition (ALD) method. In this paper, this method was applied to prepare Pt, PtCo, and PtCoPt nanoparticle catalysts on carbon support. Their activity for ethanol oxidation was studied by various electrochemical methods and the dependency of the reaction on temperature and mass transfer was evaluated. In addition, FTIR analysis was performed to confirm the reaction products. The results showed that bimetallic PtCo e...

  10. Atomic Layer Deposition of High-k Dielectrics Using Supercritical CO2

    Science.gov (United States)

    Shende, Rajesh

    2005-03-01

    Atomic layer deposition (ALD) of high-κdielectric was performed in supercritical CO2 (SCCO2), using a two-step reaction sequence. In step one, tetraethoxy silane (TEOS) precursor was injected in SCCO2 at 80-100 C and 50 MPa pressure to obtain a chemisorbed surface monolayer, which was then oxidized into SiO2 using peroxide entrained in SCCO2. ALD process was controlled by estimating precursor solubility and its mass transport with respect to the density of SCCO2, and correlating these parameters with precursor injection volume. In the ALD process, 7 pulses of precursor were used anticipating deposition of one atomic layer in each of the pulses. The thickness of the SiO2 atomic layers deposited using SCCO2 was measured by variable angle spectroscopic ellipsometry (VASE), and the C-V measurements were also performed. The result obtained using VASE indicates that there were 7 monolayers of SiO2 with total thickness of 35 å, and the dielectric constant of the deposited layers was 4.0±0.1. Our initial findings clearly demonstrate that SCCO2 is capable of atomic layer deposition of high quality dielectric films at very low process temperatures preventing interface reaction. More research is in progress to achieve ALD of HfO2 and TiO2 in SCCO2.

  11. Interfacial engineering of two-dimensional nano-structured materials by atomic layer deposition

    Science.gov (United States)

    Zhuiykov, Serge; Kawaguchi, Toshikazu; Hai, Zhenyin; Karbalaei Akbari, Mohammad; Heynderickx, Philippe M.

    2017-01-01

    Atomic Layer Deposition (ALD) is an enabling technology which provides coating and material features with significant advantages compared to other existing techniques for depositing precise nanometer-thin two-dimensional (2D) nanostructures. It is a cyclic process which relies on sequential self-terminating reactions between gas phase precursor molecules and a solid surface. ALD is especially advantageous when the film quality or thickness is critical, offering ultra-high aspect ratios. ALD provides digital thickness control to the atomic level by depositing film one atomic layer at a time, as well as pinhole-free films even over a very large and complex areas. Digital control extends to sandwiches, hetero-structures, nano-laminates, metal oxides, graded index layers and doping, and it is perfect for conformal coating and challenging 2D electrodes for various functional devices. The technique's capabilities are presented on the example of ALD-developed ultra-thin 2D tungsten oxide (WO3) over the large area of standard 4" Si substrates. The discussed advantages of ALD enable and endorse the employment of this technique for the development of hetero-nanostructure 2D semiconductors with unique properties.

  12. Effect of Pretreatment of TaN Substrates on Atomic Layer Deposition Growth of Ru Thin Films

    Institute of Scientific and Technical Information of China (English)

    ZHOU Mi; CHEN Tao; TAN Jing-Jing; RU Guo-Ping; JIANG Yu-Long; LIU Ran; QU Xin-Ping

    2007-01-01

    The polycrystalline ruthenium films are grown on TaN substrates by atomic layer deposition (ALD) using bis(cyclopentadienyl) ruthenium [RuCp2] and oxygen as ruthenium precursor and reactant respectively at a deposition temperature of 330℃. The low-energy Ar ion bombardment and Ru pre-deposition are performed to the underlying TaN substrates before ALD process in order to improve the Ru nucleation. X-ray diffraction,X-ray photoelectron spectroscopy, canning electron microscopy and atomic force microscopy are carried out to characterize the properties of ALD Ru films.The results show that the nucleation density of Ru films with Ar+ bombardment to the underlying TaN substrates is much higher than that of the ones without any pretreatment. The possible reasons are discussed.

  13. Redeposition in plasma-assisted atomic layer deposition: Silicon nitride film quality ruled by the gas residence time

    Science.gov (United States)

    Knoops, Harm C. M.; de Peuter, K.; Kessels, W. M. M.

    2015-07-01

    The requirements on the material properties and growth control of silicon nitride (SiNx) spacer films in transistors are becoming ever more stringent as scaling of transistor structures continues. One method to deposit high-quality films with excellent control is atomic layer deposition (ALD). However, depositing SiNx by ALD has turned out to be very challenging. In this work, it is shown that the plasma gas residence time τ is a key parameter for the deposition of SiNx by plasma-assisted ALD and that this parameter can be linked to a so-called "redeposition effect". This previously ignored effect, which takes place during the plasma step, is the dissociation of reaction products in the plasma and the subsequent redeposition of reaction-product fragments on the surface. For SiNx ALD using SiH2(NHtBu)2 as precursor and N2 plasma as reactant, the gas residence time τ was found to determine both SiNx film quality and the resulting growth per cycle. It is shown that redeposition can be minimized by using a short residence time resulting in high-quality films with a high wet-etch resistance (i.e., a wet-etch rate of 0.5 nm/min in buffered HF solution). Due to the fundamental nature of the redeposition effect, it is expected to play a role in many more plasma-assisted ALD processes.

  14. ZnS thin film deposited with chemical bath deposition process directed by different stirring speeds

    Science.gov (United States)

    Zhang, Y.; Dang, X. Y.; Jin, J.; Yu, T.; Li, B. Z.; He, Q.; Li, F. Y.; Sun, Y.

    2010-09-01

    In this combined film thickness, scanning electron microscopy (SEM), X-ray diffraction and optical properties study, we explore the effects of different stirring speeds on the growth and optical properties of ZnS film deposited by CBD method. From the disclosed changes of thickness of ZnS film, we conclude that film thickness is independent of the stirring speeds in the heterogeneous process (deposition time less than 40 min), but increases with the stirring speeds and/or deposition time increasing in the homogeneous process. Grazing incident X-ray diffraction (GIXRD) and the study of optical properties disclosed that the ZnS films grown with different stirring speeds show partially crystallized film and exhibit good transmittance (70-88% in the visible region), but the stirring speeds cannot give much effects on the structure and optical properties in the homogeneous process.

  15. Micromorphology of modern tills in southwestern Spitsbergen – insights into depositional and post-depositional processes

    Directory of Open Access Journals (Sweden)

    Skolasińska Katarzyna

    2016-12-01

    Full Text Available Textural properties and microstructures are commonly used properties in the analysis of Pleistocene and older glacial deposits. However, contemporary glacial deposits are seldom studied, particularly in the context of post-depositional changes. This paper presents the results of a micromorphological study of recently deposited tills in the marginal zones of Hansbreen and Torellbreen, glaciers in southwestern Spitsbergen. The main objectives of this study were to compare modern tills deposited in subglacial and supraglacial conditions, as well as tills that were freshly released from ice with those laid down several decades ago. The investigated tills are primarily composed of large clasts of metamorphic rocks and represent coarse-grained, matrix-supported diamictons. The tills reveal several characteristic features for ductile (e.g. turbate structures and brittle (e.g. lineations, microshears deformations, which have been considered to be indicative of subglacial conditions. In supraglacial tills, the same structures are common as in the subglacial deposits, which points to the preservation of the primary features, though the sediment was transferred up to the glacier surface due to basal ice layer deformation and redeposited as slumps, or to formation of similar structures due to short-distance sediment re-deposition by mass flows. This study revealed that it might not be possible to distinguish subglacial and supraglacial tills on the basis of micromorphology if the latter are derived from a subglacial position. The only noted difference was the presence of iron oxide cementation zones and carbonate dissolution features in supraglacial tills. These features were found in tills that were deposited at least a few years ago and are interpreted to be induced by early post-depositional processes involving porewater/sediment interactions.

  16. Enhancing the platinum atomic layer deposition infiltration depth inside anodic alumina nanoporous membrane

    Energy Technology Data Exchange (ETDEWEB)

    Vaish, Amit, E-mail: anv@udel.edu; Krueger, Susan; Dimitriou, Michael; Majkrzak, Charles [National Institute of Standards and Technology (NIST) Center for Neutron Research, Gaithersburg, MD 20899-8313 (United States); Vanderah, David J. [Institute for Bioscience and Biotechnology Research, NIST, Rockville, Maryland 20850 (United States); Chen, Lei, E-mail: lei.chen@nist.gov [NIST Center for Nanoscale Science and Technology, Gaithersburg, Maryland 20899-8313 (United States); Gawrisch, Klaus [Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892 (United States)

    2015-01-15

    Nanoporous platinum membranes can be straightforwardly fabricated by forming a Pt coating inside the nanopores of anodic alumina membranes (AAO) using atomic layer deposition (ALD). However, the high-aspect-ratio of AAO makes Pt ALD very challenging. By tuning the process deposition temperature and precursor exposure time, enhanced infiltration depth along with conformal coating was achieved for Pt ALD inside the AAO templates. Cross-sectional scanning electron microscopy/energy dispersive x-ray spectroscopy and small angle neutron scattering were employed to analyze the Pt coverage and thickness inside the AAO nanopores. Additionally, one application of platinum-coated membrane was demonstrated by creating a high-density protein-functionalized interface.

  17. Thermal Modeling of Direct Digital Melt-Deposition Processes

    Science.gov (United States)

    Cooper, K. P.; Lambrakos, S. G.

    2011-02-01

    Additive manufacturing involves creating three-dimensional (3D) objects by depositing materials layer-by-layer. The freeform nature of the method permits the production of components with complex geometry. Deposition processes provide one more capability, which is the addition of multiple materials in a discrete manner to create "heterogeneous" objects with locally controlled composition and microstructure. The result is direct digital manufacturing (DDM) by which dissimilar materials are added voxel-by-voxel (a voxel is volumetric pixel) following a predetermined tool-path. A typical example is functionally gradient material such as a gear with a tough core and a wear-resistant surface. The inherent complexity of DDM processes is such that process modeling based on direct physics-based theory is difficult, especially due to a lack of temperature-dependent thermophysical properties and particularly when dealing with melt-deposition processes. In order to overcome this difficulty, an inverse problem approach is proposed for the development of thermal models that can represent multi-material, direct digital melt deposition. This approach is based on the construction of a numerical-algorithmic framework for modeling anisotropic diffusivity such as that which would occur during energy deposition within a heterogeneous workpiece. This framework consists of path-weighted integral formulations of heat diffusion according to spatial variations in material composition and requires consideration of parameter sensitivity issues.

  18. Spatial atmospheric ALD of functional layers for CIGS Solar Cells

    NARCIS (Netherlands)

    Illiberi, A.; Frijters, C.; Balder, J.E.; Poodt, P.W.G.; Roozeboom, F.

    2015-01-01

    Spatial Atmosperic Atomic Layer Depositon combines the advantages of temporal ALD, i.e. excellent control of film composition and uniformity over large area substrates, with high growth rages (up tot nm/s). In this paper we present a short overview of our research acctivity carried out on S-ALD of f

  19. Nano-scale gap filling and mechanism of deposit-etch-deposit process for phase-change material

    Institute of Scientific and Technical Information of China (English)

    Ren Wan-Chun; Liu Bo; Song Zhi-Tang; Xiang Yang-Hui; Wang Zong-Tao; Zhang Bei-Chao; Feng Song-Lin

    2012-01-01

    Ge2Sb2Te5 gap filling is one of the key processes for phase-change random access memory manufacture.Physical vapor deposition is the mainstream method of Ge2Sb2Te5 film deposition due to its advantages of film quality,purity,and accurate composition control.However,the conventional physical vapor deposition process cannot meet the gapfilling requirement with the critical device dimension scaling down to 90 nm or below.In this study,we find that the deposit-etch-deposit process shows better gap-filling capability and scalability than the single-step deposition process,especially at the nano-scale critical dimension.The gap-filling mechanism of the deposit-etch-deposit process was briefly discussed.We also find that re-deposition of phase-change material from via the sidewall to via the bottom by argon ion bombardment during the etch step was a key ingredient for the final good gap filling.We achieve void-free gap filling of phase-change material on the 45-nm via the two-cycle deposit-etch-deposit process.We gain a rather comprehensive insight into the mechanism of deposit-etch-deposit process and propose a potential gap-filling solution for over 45-nm technology nodes for phase-change random access memory.

  20. Synthesis of platinum nanoparticle electrocatalysts by atomic layer deposition

    Science.gov (United States)

    Lubers, Alia Marie

    Demand for energy continues to increase, and without alternatives to fossil fuel combustion the effects on our environment will become increasingly severe. Fuel cells offer a promising improvement on current methods of energy generation; they are able to convert hydrogen fuel into electricity with a theoretical efficiency of up to 83% and interface smoothly with renewable hydrogen production. Fuel cells can replace internal combustion engines in vehicles and are used in stationary applications to power homes and businesses. The efficiency of a fuel cell is maximized by its catalyst, which is often composed of platinum nanoparticles supported on carbon. Economical production of fuel cell catalysts will promote adoption of this technology. Atomic layer deposition (ALD) is a possible method for producing catalysts at a large scale when employed in a fluidized bed. ALD relies on sequential dosing of gas-phase precursors to grow a material layer by layer. We have synthesized platinum nanoparticles on a carbon particle support (Pt/C) by ALD for use in proton exchange membrane fuel cells (PEMFCs) and electrochemical hydrogen pumps. Platinum nanoparticles with different characteristics were deposited by changing two chemistries: the carbon substrate through functionalization; and the deposition process by use of either oxygen or hydrogen as ligand removing reactants. The metal depositing reactant was trimethyl(methylcyclopentadienyl)platinum(IV). Functionalizing the carbon substrate increased nucleation during deposition resulting in smaller and more dispersed nanoparticles. Use of hydrogen produced smaller nanoparticles than oxygen, due to a gentler hydrogenation reaction compared to using oxygen's destructive combustion reaction. Synthesized Pt/C materials were used as catalysts in an electrochemical hydrogen pump, a device used to separate hydrogen fuel from contaminants. Catalysts deposited by ALD on functionalized carbon using a hydrogen chemistry were the most

  1. Near-interface Si substrate 3d metal contamination during atomic layer deposition processing detected by electron spin resonance

    Science.gov (United States)

    Nguyen, A. P. D.; Stesmans, A.; Hiller, D.; Zacharias, M.

    2012-06-01

    A K- and Q-band electron spin resonance (ESR) study has been carried out on (100)Si/SiO2 entities manufactured by low temperature (150 °C) atomic layer deposition (ALD) of a high-quality SiO2 layer on Si using 3-aminopropyltriethoxysilane, H2O, and ozone in a three-step process. Whereas previous work has demonstrated the high quality of the deposited SiO2 layer, the current ESR analysis reports on the tracing of growth-related contamination of near interface Si substrate layers by two transition metals. This includes, first, detection of the signal of interstitial Cr+ (S = 5/2) impurities in c-Si, characterized by an isotropic central g value of 1.9980 ± 0.0002, an isotropic 53Cr (I = 3/2) hyperfine interaction of splitting Aiso = 11.8 G, and cubic crystal field splitting parameter a = +32.2 G, well in agreement with the known bulk c-Si case; A small anisotropic contribution to the hyperfine interaction has additionally been revealed. The total Cr+ defect density is inferred as ˜5 × 1011 cm-2. Second, a single signal is observed at isotropic g = 2.070 ± 0.001, corresponding to interstitial Fe impurities (Fei)0 (S = 1) positioned in a c-Si matrix. Defect density depth profiling reveals the impurities to be confined to a few μm thick Si substrate top layer, the density decaying exponential-like from the Si/SiO2 interface inward the Si substrate. The total of the results points to a contamination of reactor-environment origin, connected with the layer deposition process. It concerns a weak contamination, in which detection the ESR technique emerges as a powerful technique able to unveil very low levels of contamination of near-surface Si substrate layers.

  2. Powder Flux Regulation in the Laser Material Deposition Process

    Science.gov (United States)

    Arrizubieta, Jon Iñaki; Wegener, Maximiliam; Arntz, Kristian; Lamikiz, Aitzol; Ruiz, Jose Exequiel

    In the present research work a powder flux regulation system has been designed, developed and validated with the aim of improving the Laser Material Deposition (LMD) process. In this process, the amount of deposited material per substrate surface unit area depends on the real feed rate of the nozzle. Therefore, a regulation system based on a solenoid valve has been installed at the nozzle entrance in order to control the powder flux. The powder flux control has been performed based on the machine real feed rate, which is compared with the programmed feed rate. An instantaneous velocity error is calculated and the powder flow is controlled as a function of this variation using Pulse Width Modulation (PWM) signals. Thereby, in zones where the Laser Material Deposition machine reduces the feed rate due to a trajectory change, powder accumulation can be avoided and the generated clads would present a homogeneous shape.

  3. Plasma Processes : Microwave plasma deposition of diamond like carbon coatings

    Indian Academy of Sciences (India)

    D S Patil; K Ramachandran; N Venkatramani; M Pandey; R D'Cunha

    2000-11-01

    The promising applications of the microwave plasmas have been appearing in the fields of chemical processes and semiconductor manufacturing. Applications include surface deposition of all types including diamond/diamond like carbon (DLC) coatings, etching of semiconductors, promotion of organic reactions, etching of polymers to improve bonding of the other materials etc. With a 2.45 GHz, 700 W, microwave induced plasma chemical vapor deposition (CVD) system set up in our laboratory we have deposited diamond like carbon coatings. The microwave plasma generation was effected using a wave guide single mode applicator. We have deposited DLC coatings on the substrates like stainless steel, Cu–Be, Cu and Si. The deposited coatings have been characterized by FTIR, Raman spectroscopy and ellipsometric techniques. The results show that we have achieved depositing ∼ 95% sp3 bonded carbon in the films. The films are uniform with golden yellow color. The films are found to be excellent insulators. The ellipsometric measurements of optical constant on silicon substrates indicate that the films are transparent above 900 nm.

  4. ALD mediated heparin grafting on nitinol for self-expanded carotid stents.

    Science.gov (United States)

    Wang, Fei; Zhang, Yan; Chen, Xiumian; Leng, Bing; Guo, Xin; Zhang, Tao

    2016-07-01

    Carotid-artery atherosclerosis is a common cause of ischemic stroke. Carotid-artery stenting (CAS) is one of the most effective treatments. However, In-stent restenosis (ISR) and re-endothelialization delay are two major issues of intravascular stent which affect clinical safety and reduce effects. In this study, atomic layer deposition (ALD) technology was applied to deposit a layer (10nm) of Al2O3 on Nitinol surface as an intermediate functional layer. The alumina covered surface was then modified with a coupling agent 3-aminopropyltriethoxysilane (APS) and heparin sequentially in order to improve the hemocompatibility of Nitinol stents. The successful graft of APS and heparin onto Nitinol was proven by X-ray photoelectron spectroscopy. Furthermore, the predicted improvement in the biocompatibilities of modified Nitinol was confirmed by water contact angle measurement, protein adsorption, platelet adhesion, and plasma recalcification time determination. The results of hemolysis assay, cell proliferation and cytotoxicity tests revealed that the grafting of heparin on NiTi kept the original positive performance of nitinol material. The results indicate that ALD technology is of great potential for the manufacture of medical devices, especially for surface modifications and functionalization. ALD technology can help with modifications of inert metallic surfaces and therefore benefit implantable medical devices, especially intravascular stents.

  5. Structure-Dependent Mechanical Properties of ALD-Grown Nanocrystalline BiFeO3 Multiferroics

    Directory of Open Access Journals (Sweden)

    Anna Majtyka

    2016-01-01

    Full Text Available The present paper pertains to mechanical properties and structure of nanocrystalline multiferroic BeFiO3 (BFO thin films, grown by atomic layer deposition (ALD on the Si/SiO2/Pt substrate. The usage of sharp-tip-nanoindentation and multiple techniques of structure examination, namely, grazing incidence X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectrometry, enabled us to detect changes in elastic properties (95 GPa≤E≤118 GPa and hardness (4.50 GPa≤H≤7.96 GPa of BFO after stages of annealing and observe their relation to the material’s structural evolution. Our experiments point towards an increase in structural homogeneity of the samples annealed for a longer time. To our best knowledge, the present report constitutes the first disclosure of nanoindentation mechanical characteristics of ALD-fabricated BeFiO3, providing a new insight into the phenomena that accompany structure formation and development of nanocrystalline multiferroics. We believe that our systematic characterization of the BFO layers carried out at consecutive stages of their deposition provides pertinent information which is needed to control and optimize its ALD fabrication.

  6. Application of laser assisted cold spraying process for metal deposition

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2014-02-01

    Full Text Available Laser assisted cold spraying (LACS) process is a hybrid technique that uses laser and cold spray to deposit solid powders on metal substrates. For bonding to occur, the particle velocities must be supersonic which are achieved by entraining...

  7. Effect of corona pre-treatment on the performance of gas barrier layers applied by atomic layer deposition onto polymer-coated paperboard

    Energy Technology Data Exchange (ETDEWEB)

    Hirvikorpi, Terhi, E-mail: terhi.hirvikorpi@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, P.O. Box 1000, FI-02044 VTT Espoo (Finland); Vaehae-Nissi, Mika, E-mail: mika.vaha-nissi@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, P.O. Box 1000, FI-02044 VTT Espoo (Finland); Harlin, Ali, E-mail: ali.harlin@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, P.O. Box 1000, FI-02044 VTT Espoo (Finland); Marles, Jaana, E-mail: jaana.marles@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Miikkulainen, Ville, E-mail: ville.miikkulainen@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Karppinen, Maarit, E-mail: maarit.karppinen@tkk.fi [Aalto University School of Technology and Science, Laboratory of Inorganic Chemistry, Kemistintie 1A, Espoo, P.O. Box 16100, 00076 Aalto (Finland)

    2010-11-15

    The effect of corona pre-treatment on the performance of Al{sub 2}O{sub 3} and SiO{sub 2} gas barrier layers applied by atomic layer deposition onto polymer-coated paperboards was studied. Both polyethylene and polylactide coated paperboards were corona treated prior to ALD. Corona treatment increased surface energies of the paperboard substrates, and this effect was still observed after several days. Al{sub 2}O{sub 3} and SiO{sub 2} films were grown on top of the polymer coatings at temperature of 100 deg. C using the atomic layer deposition (ALD) technique. For SiO{sub 2} depositions a new precursor, bis(diethylamido) silane, was used. The positive effect of the corona pre-treatment on the barrier properties of the polymer-coated paperboards with the ALD-grown layers was more significant with polyethylene coated paperboard and with thin deposited layers (shorter ALD process). SiO{sub 2} performed similarly to Al{sub 2}O{sub 3} with the PE coated board when it comes to the oxygen barrier, while the performance of SiO{sub 2} with the biopolymer-coated board was more moderate. The effect of corona pre-treatment was negligible or even negative with the biopolymer-coated board. The ALD film growth and the effect of corona treatment on different substrates require further investigation.

  8. Recent Development of Advanced Electrode Materials by Atomic Layer Deposition for Electrochemical Energy Storage.

    Science.gov (United States)

    Guan, Cao; Wang, John

    2016-10-01

    Electrode materials play a decisive role in almost all electrochemical energy storage devices, determining their overall performance. Proper selection, design and fabrication of electrode materials have thus been regarded as one of the most critical steps in achieving high electrochemical energy storage performance. As an advanced nanotechnology for thin films and surfaces with conformal interfacial features and well controllable deposition thickness, atomic layer deposition (ALD) has been successfully developed for deposition and surface modification of electrode materials, where there are considerable issues of interfacial and surface chemistry at atomic and nanometer scale. In addition, ALD has shown great potential in construction of novel nanostructured active materials that otherwise can be hardly obtained by other processing techniques, such as those solution-based processing and chemical vapor deposition (CVD) techniques. This review focuses on the recent development of ALD for the design and delivery of advanced electrode materials in electrochemical energy storage devices, where typical examples will be highlighted and analyzed, and the merits and challenges of ALD for applications in energy storage will also be discussed.

  9. Low temperature plasma-enhanced ALD TiN ultrathin films for Hf{sub 0.5}Zr{sub 0.5}O{sub 2}-based ferroelectric MIM structures

    Energy Technology Data Exchange (ETDEWEB)

    Kozodaev, M.G.; Chernikova, A.G.; Markeev, A.M. [Moscow Institute of Physics and Technology, Institutsky Lane 9, Dolgoprudny, Moscow Region 141700 (Russian Federation); Lebedinskii, Y.Y. [Moscow Institute of Physics and Technology, Institutsky Lane 9, Dolgoprudny, Moscow Region 141700 (Russian Federation); National Research Nuclear University MEPhI, Moscow Engineering Physics Institute, Kashirskoye Shosse 31, 115409 Moscow (Russian Federation); Polyakov, S.N. [Technological Institute for Superhard and Novel Carbon Materials, Tsentral' naya str. 7a, 142190, Troitsk, Moscow (Russian Federation)

    2017-06-15

    In this work chemical and electrical properties of TiN films, grown by low temperature plasma-enhanced atomic layer deposition (PE-ALD) process from TiCl{sub 4} and NH{sub 3}, were investigated. Electrical resistivity as low as 250 μOhm x cm, as well as the lowest Cl impurity content, was achieved at 320 C. Full-ALD Hf{sub 0.5}Zr{sub 0.5}O{sub 2}-based metal-ferroelectric-metal capacitor with TiN electrodes was fabricated and its electrical properties were investigated. It was also shown that the proposed PE-ALD process provides an early film continuity, which was confirmed by ultrathin fully continuous film growth. Such ultrathin (3 nm) and fully continuous TiN film was also successfully implemented as the top electrode to Hf{sub 0.5}Zr{sub 0.5}O{sub 2}-based ferroelectric capacitor. Angle-resolved X-ray photoelectron spectroscopy (AR-XPS) was used for its thickness determination and a visible wake-up effect in underlying Hf{sub 0.5}Zr{sub 0.5}O{sub 2} layer was clearly observed. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. ALD Produced B{sub 2}O{sub 3}, Al{sub 2}O{sub 3} and TiO{sub 2} Coatings on Gd{sub 2}O{sub 3} Burnable Poison Nanoparticles and Carbonaceous TRISO Coating Layers

    Energy Technology Data Exchange (ETDEWEB)

    Weimer, Alan

    2012-11-26

    This project will demonstrate the feasibility of using atomic layer deposition (ALD) to apply ultrathin neutron-absorbing, corrosion-resistant layers consisting of ceramics, metals, or combinations thereof, on particles for enhanced nuclear fuel pellets. Current pellet coating technology utilizes chemical vapor deposition (CVD) in a fluidized bed reactor to deposit thick, porous layers of C (or PyC) and SiC. These graphitic/carbide materials degrade over time owing to fission product bombardment, active oxidation, thermal management issues, and long-term irradiation effects. ALD can be used to deposit potential ceramic barrier materials of interest, including ZrO{sub 2}, Y{sub 2}O{sub 3}:ZrO{sub 2} (YSZ), Al{sub 2}O{sub 3}, and TiO{sub 2}, or neutron-absorbing materials, namely B (in BN or B{sub 2}O{sub 3}) and Gd (in Gd{sub 2}O{sub 3}). This project consists of a two-pronged approach to integrate ALD into the next-generation nuclear plant (NGNP) fuel pellet manufacturing process:

  11. Morphology Simulation for Ion-Assisted Deposition Process

    Institute of Scientific and Technical Information of China (English)

    Jenn-SenLin; Shin-PonJu; Jian-MingLu

    2004-01-01

    The molecular dynamics simulation is applied to investigate the lnfluence of the incident 1on energy ana mclident angular distribution upon ion-assisted deposition process. The Cu-Cu and Ar-Cu interactions are modeled using the many body tight-binding potential and the Moliere potential, respectively, and the interface width is used to characterize the surface roughness properties at both transient and final state conditions. The results show that the surface roughness of the deposition film is lower when more Ar-to-Cu ratio is used at the same incident energy and angle. For the relative low or high incident energy, the film morphologies are not sensitive to the incident angle. However, if the incident energy of the argon ions is too high, the film morphology will be worse than that without using the ion-assisted deposition.

  12. TiO{sub 2} anatase films obtained by direct liquid injection atomic layer deposition at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Avril, L., E-mail: ludovic.avril@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Reymond-Laruinaz, S. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Decams, J.M. [Annealsys, rue de la Vieille Poste, 34055 Montpellier Cedex 1 (France); Bruyère, S.; Potin, V.; Lucas, M.C. Marco de; Imhoff, L. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France)

    2014-01-01

    TiO{sub 2} thin films were grown by direct liquid injection atomic layer deposition (DLI-ALD) with infrared rapid thermal heating using titanium tetraisopropoxide and water as precursors. This titanium tetraisopropoxide/water process exhibited a growth rate of 0.018 nm/cycle in a self-limited ALD growth mode at 280 °C. Scanning electron microscopy and atomic force microscopy analyses have shown a smooth surface with a low roughness. XPS results demonstrated that the films were pure and close to the TiO{sub 2} stoichiometric composition in depth. Raman spectroscopy revealed that the films were crystallized to the anatase structure in the as-deposited state at low temperature without necessity of high temperature annealing. Results obtained demonstrate that the liquid injection ALD is an efficient method of elaborating titanium oxide films using titanium tetraisopropoxide as precursor.

  13. Activation of Metal-Organic Precursors by Electron Bombardment in the Gas Phase for Enhanced Deposition of Solid Films.

    Science.gov (United States)

    Sun, Huaxing; Qin, Xiangdong; Zaera, Francisco

    2012-09-01

    The incorporation of gas-phase electron-impact ionization and activation of metal-organic compounds into atomic layer deposition (ALD) processes is reported as a way to enhance film growth with stable precursors. Specifically, it is shown here that gas-phase activation of methylcyclopentadienylmanganese tricarbonyl, MeCpMn(CO)3, which was accomplished by using a typical nude ion gauge employed in many ultrahigh-vacuum (UHV) studies, enhances its dissociative adsorption on silicon surfaces, affording the design of ALD cycles with more extensive Mn deposition and at lower temperatures. Significantly higher Mn uptakes were demonstrated by X-ray photoelectron spectroscopy (XPS) on both silicon dioxide films and on Si(100) wafers Ar(+)-sputtered to remove their native oxide layer. The effectiveness of this electron-impact activation approach in ALD is explained in terms of the cracking patterns seen in mass spectrometry for the metal-organic precursor used.

  14. Flat metallic surface gratings with sub-10 nm gaps controlled by atomic-layer deposition

    Science.gov (United States)

    Chen, Borui; Ji, Dengxin; Cheney, Alec; Zhang, Nan; Song, Haomin; Zeng, Xie; Thomay, Tim; Gan, Qiaoqiang; Cartwright, Alexander

    2016-09-01

    Atomic layer lithography is a recently reported new technology to fabricate deep-subwavelength features down to 1-2 nm, based on combinations of electron beam lithography (EBL) and atomic layer deposition (ALD). However, the patterning area is relatively small as limited by EBL, and the fabrication yield is not very high due to technical challenges. Here we report an improved procedure to fabricate flat metallic surfaces with sub-10 nm features based on ALD processes. To demonstrate the scalability of the new manufacturing method, we combine the ALD process with large area optical interference patterning, which is particularly promising for the development of practical applications for nanoelectronics and nanophotonics with extremely strong confinement of electromagnetic fields.

  15. Characterization of 1064nm laser-induced damage on antireflection coatings grown by atomic layer deposition

    Science.gov (United States)

    Liu, Zhichao; Wei, Yaowei; Chen, Songlin; Luo, Jin; Ma, Ping

    2011-12-01

    Damage tests were carried out to measure the laser resistance of Al2O3/TiO2 and Al2O3/HfO2 antireflection coatings at 1064nm grown by atomic layer deposition (ALD). The S-on-1 and R-on-1 damage results are given. It's interesting to find that ALD coatings damage performance seems closed to those grown by conventional e-beam evaporation process. For Al2O3/TiO2 coatings, the grown temperature will impact the damage resistance of thin films. Crystallization of TiO2 layer at higher temperature could play an importance role as absorption defects that reduced the LIDT of coatings. In addition, it is found that using inorganic compound instead of organic compound as precursors for ALD process can effective prevent residual carbon in films and will increase the LIDT of coatings.

  16. Microscratch testing method for systematic evaluation of the adhesion of atomic layer deposited thin films on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Kilpi, Lauri, E-mail: Lauri.Kilpi@vtt.fi; Ylivaara, Oili M. E.; Vaajoki, Antti; Puurunen, Riikka L.; Ronkainen, Helena [VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT (Finland); Malm, Jari [Department of Physics, University of Jyväskylä, P.O. Box 35, Jyväskylä 40014 (Finland); Sintonen, Sakari [Department of Micro- and Nanosciences, Aalto University School of Electrical Engineering, P.O. Box 13500, FI-00076 AALTO (Finland); Tuominen, Marko [ASM Microchemistry Oy, Pietari Kalmin katu 1 F 2, FIN-00560 Helsinki (Finland)

    2016-01-15

    The scratch test method is widely used for adhesion evaluation of thin films and coatings. Usual critical load criteria designed for scratch testing of coatings were not applicable to thin atomic layer deposition (ALD) films on silicon wafers. Thus, the bases for critical load evaluation were established and the critical loads suitable for ALD coating adhesion evaluation on silicon wafers were determined in this paper as L{sub CSi1}, L{sub CSi2}, L{sub CALD1}, and L{sub CALD2}, representing the failure points of the silicon substrate and the coating delamination points of the ALD coating. The adhesion performance of the ALD Al{sub 2}O{sub 3}, TiO{sub 2}, TiN, and TaCN+Ru coatings with a thickness range between 20 and 600 nm and deposition temperature between 30 and 410 °C on silicon wafers was investigated. In addition, the impact of the annealing process after deposition on adhesion was evaluated for selected cases. The tests carried out using scratch and Scotch tape test showed that the coating deposition and annealing temperature, thickness of the coating, and surface pretreatments of the Si wafer had an impact on the adhesion performance of the ALD coatings on the silicon wafer. There was also an improved load carrying capacity due to Al{sub 2}O{sub 3}, the magnitude of which depended on the coating thickness and the deposition temperature. The tape tests were carried out for selected coatings as a comparison. The results show that the scratch test is a useful and applicable tool for adhesion evaluation of ALD coatings, even when carried out for thin (20 nm thick) coatings.

  17. A Modified Surface on Titanium Deposited by a Blasting Process

    Directory of Open Access Journals (Sweden)

    Caroline O’Sullivan

    2011-09-01

    Full Text Available Hydroxyapatite (HA coating of hard tissue implants is widely employed for its biocompatible and osteoconductive properties as well as its improved mechanical properties. Plasma technology is the principal deposition process for coating HA on bioactive metals for this application. However, thermal decomposition of HA can occur during the plasma deposition process, resulting in coating variability in terms of purity, uniformity and crystallinity, which can lead to implant failure caused by aseptic loosening. In this study, CoBlastTM, a novel blasting process has been used to successfully modify a titanium (V substrate with a HA treatment using a dopant/abrasive regime. The impact of a series of apatitic abrasives under the trade name MCD, was investigated to determine the effect of abrasive particle size on the surface properties of both microblast (abrasive only and CoBlast (HA/abrasive treatments. The resultant HA treated substrates were compared to substrates treated with abrasive only (microblasted and an untreated Ti. The HA powder, apatitic abrasives and the treated substrates were characterized for chemical composition, coating coverage, crystallinity and topography including surface roughness. The results show that the surface roughness of the HA blasted modification was affected by the particle size of the apatitic abrasives used. The CoBlast process did not alter the chemistry of the crystalline HA during deposition. Cell proliferation on the HA surface was also assessed, which demonstrated enhanced osteo-viability compared to the microblast and blank Ti. This study demonstrates the ability of the CoBlast process to deposit HA coatings with a range of surface properties onto Ti substrates. The ability of the CoBlast technology to offer diversity in modifying surface topography offers exciting new prospects in tailoring the properties of medical devices for applications ranging from dental to orthopedic settings.

  18. Numerical modeling of consolidation processes in hydraulically deposited soils

    Science.gov (United States)

    Brink, Nicholas Robert

    Hydraulically deposited soils are encountered in many common engineering applications including mine tailing and geotextile tube fills, though the consolidation process for such soils is highly nonlinear and requires the use of advanced numerical techniques to provide accurate predictions. Several commercially available finite element codes poses the ability to model soil consolidation, and it was the goal of this research to assess the ability of two of these codes, ABAQUS and PLAXIS, to model the large-strain, two-dimensional consolidation processes which occur in hydraulically deposited soils. A series of one- and two-dimensionally drained rectangular models were first created to assess the limitations of ABAQUS and PLAXIS when modeling consolidation of highly compressible soils. Then, geotextile tube and TSF models were created to represent actual scenarios which might be encountered in engineering practice. Several limitations were discovered, including the existence of a minimum preconsolidation stress below which numerical solutions become unstable.

  19. Atomic layer deposition on polymer fibers and fabrics for multifunctional and electronic textiles

    Energy Technology Data Exchange (ETDEWEB)

    Brozena, Alexandra H.; Oldham, Christopher J.; Parsons, Gregory N., E-mail: gnp@ncsu.edu [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905 (United States)

    2016-01-15

    Textile materials, including woven cotton, polymer knit fabrics, and synthetic nonwoven fiber mats, are being explored as low-cost, flexible, and light-weight platforms for wearable electronic sensing, communication, energy generation, and storage. The natural porosity and high surface area in textiles is also useful for new applications in environmental protection, chemical decontamination, pharmaceutical and chemical manufacturing, catalytic support, tissue regeneration, and others. These applications raise opportunities for new chemistries, chemical processes, biological coupling, and nanodevice systems that can readily combine with textile manufacturing to create new “multifunctional” fabrics. Atomic layer deposition (ALD) has a unique ability to form highly uniform and conformal thin films at low processing temperature on nonuniform high aspect ratio surfaces. Recent research shows how ALD can coat, modify, and otherwise improve polymer fibers and textiles by incorporating new materials for viable electronic and other multifunctional capabilities. This article provides a current overview of the understanding of ALD coating and modification of textiles, including current capabilities and outstanding problems, with the goal of providing a starting point for further research and advances in this field. After a brief introduction to textile materials and current textile treatment methods, the authors discuss unique properties of ALD-coated textiles, followed by a review of recent electronic and multifunctional textiles that use ALD coatings either as direct functional components or as critical nucleation layers for active materials integration. The article concludes with possible future directions for ALD on textiles, including the challenges in materials, manufacturing, and manufacturing integration that must be overcome for ALD to reach its full potential in electronic and other emerging multifunctional textile systems.

  20. The influence of surface preparation on low temperature HfO{sub 2} ALD on InGaAs (001) and (110) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kent, Tyler; Edmonds, Mary; Kummel, Andrew C. [Materials Science and Engineering Department, University of California, San Diego, California 9500 (United States); Tang, Kechao; Negara, Muhammad Adi; McIntyre, Paul [Materials Science and Engineering Department, Stanford University, Stanford, California 94305 (United States); Chobpattana, Varistha; Mitchell, William [Materials Department, University of California, Santa Barbara, California 93106 (United States); Sahu, Bhagawan; Galatage, Rohit [Global Foundries, 2600 Great America Way, Santa Clara, California 95054 (United States); Droopad, Ravi [Department of Physics, Texas State University, San Marcos, Texas 78666 (United States)

    2015-10-28

    Current logic devices rely on 3D architectures, such as the tri-gate field effect transistor (finFET), which utilize the (001) and (110) crystal faces simultaneously thus requiring passivation methods for the (110) face in order to ensure a pristine 3D surface prior to further processing. Scanning tunneling microscopy (STM), x-ray photoelectron spectroscopy (XPS), and correlated electrical measurement on MOSCAPs were utilized to compare the effects of a previously developed in situ pre-atomic layer deposition (ALD) surface clean on the InGaAs (001) and (110) surfaces. Ex situ wet cleans are very effective on the (001) surface but not the (110) surface. Capacitance voltage indicated the (001) surface with no buffered oxide etch had a higher C{sub max} hypothesized to be a result of poor nucleation of HfO{sub 2} on the native oxide. An in situ pre-ALD surface clean employing both atomic H and trimethylaluminum (TMA) pre-pulsing, developed by Chobpattana et al. and Carter et al. for the (001) surface, was demonstrated to be effective on the (110) surface for producing low D{sub it} high C{sub ox} MOSCAPs. Including TMA in the pre-ALD surface clean resulted in reduction of the magnitude of the interface state capacitance. The XPS studies show the role of atomic H pre-pulsing is to remove both carbon and oxygen while STM shows the role of TMA pre-pulsing is to eliminate H induced etching. Devices fabricated at 120 °C and 300 °C were compared.

  1. History of atomic layer deposition and its relationship with the American Vacuum Society

    NARCIS (Netherlands)

    Parsons, G.N.; Elam, J.W.; George, S.M.; Haukka, S.; Jeon, H.; Kessels, W.M.M.; Leskelä, M.; Poodt, P.; Ritala, M.; Rossnagel, S.M.

    2013-01-01

    This article explores the history of atomic layer deposition (ALD) and its relationship with the American Vacuum Society (AVS). The authors describe the origin and history of ALD science in the 1960s and 1970s. They also report on how the science and technology of ALD progressed through the 1990s an

  2. Characteristics of Al-doped ZnO films grown by atomic layer deposition for silicon nanowire photovoltaic device.

    Science.gov (United States)

    Oh, Byeong-Yun; Han, Jin-Woo; Seo, Dae-Shik; Kim, Kwang-Young; Baek, Seong-Ho; Jang, Hwan Soo; Kim, Jae Hyun

    2012-07-01

    We report the structural, electrical, and optical characteristics of Al-doped ZnO (ZnO:Al) films deposited on glass by atomic layer deposition (ALD) with various Al2O3 film contents for use as transparent electrodes. Unlike films fabricated by a sputtering method, the diffraction peak position of the films deposited by ALD progressively moved to a higher angle with increasing Al2O3 film content. This indicates that Zn sites were effectively replaced by Al, due to layer-by-layer growth mechanism of ALD process which is based on alternate self-limiting surface chemical reactions. By adjusting the Al2O3 film content, a ZnO:Al film with low electrical resistivity (9.84 x 10(-4) Omega cm) was obtained at an Al2O3 film content of 3.17%, where the Al concentration, carrier mobility, optical transmittance, and bandgap energy were 2.8 wt%, 11.20 cm2 V(-1) s(-1), 94.23%, and 3.6 eV, respectively. Moreover, the estimated figure of merit value of our best sample was 8.2 m7Omega(-1). These results suggest that ZnO:Al films deposited by ALD could be useful for electronic devices in which especially require 3-dimensional conformal deposition of the transparent electrode and surface passivation.

  3. Atmospheric spatial atomic layer deposition of Zn(O,S) buffer layer for Cu(In,Ga)Se2 solar cells

    NARCIS (Netherlands)

    Frijters, C.H.; Poodt, P.; Illeberi, A.

    2016-01-01

    Zinc oxysulfide has been grown by spatial atomic layer deposition (S-ALD) and successfully applied as buffer layer in Cu(In, Ga)Se2 (CIGS) solar cells. S-ALD combines high deposition rates (up to nm/s) with the advantages of conventional ALD, i.e. excellent control of film composition and superior u

  4. The Use of Feature Parameters to Asses Barrier Properties of ALD coatings for Flexible PV Substrates

    Science.gov (United States)

    Blunt, Liam; Robbins, David; Fleming, Leigh; Elrawemi, Mohamed

    2014-03-01

    This paper reports on the recent work carried out as part of the EU funded NanoMend project. The project seeks to develop integrated process inspection, cleaning, repair and control systems for nano-scale thin films on large area substrates. In the present study flexible photovoltaic films have been the substrate of interest. Flexible PV films are the subject of significant development at present and the latest films have efficiencies at or beyond the level of Si based rigid PV modules. These flexible devices are fabricated on polymer film by the repeated deposition, and patterning, of thin layer materials using roll-to-roll processes, where the whole film is approximately 3um thick prior to encapsulation. Whilst flexible films offer significant advantages in terms of mass and the possibility of building integration (BIPV) they are at present susceptible to long term environmental degradation as a result of water vapor transmission through the barrier layers to the CIGS (Copper Indium Gallium Selenide CuInxGa(1-x)Se2) PV cells thus causing electrical shorts and efficiency drops. Environmental protection of the GIGS cell is provided by a thin (40nm) barrier coating of Al2O3. The highly conformal aluminium oxide barrier layer is produced by atomic layer deposition (ALD) where, the ultra-thin Al2O3 layer is deposited onto polymer thin films before these films encapsulate the PV cell. The surface of the starting polymer film must be of very high quality in order to avoid creating defects in the device layers. Since these defects reduce manufacturing yield, in order to prevent them, a further thin polymer coating (planarization layer) is generally applied to the polymer film prior to deposition. The presence of surface irregularities on the uncoated film can create defects within the nanometre-scale, aluminium oxide, barrier layer and these are measured and characterised. This paper begins by reporting the results of early stage measurements conducted to characterise

  5. Stepwise mechanism and H2O-assisted hydrolysis in atomic layer deposition of SiO2 without a catalyst.

    Science.gov (United States)

    Fang, Guo-Yong; Xu, Li-Na; Wang, Lai-Guo; Cao, Yan-Qiang; Wu, Di; Li, Ai-Dong

    2015-01-01

    Atomic layer deposition (ALD) is a powerful deposition technique for constructing uniform, conformal, and ultrathin films in microelectronics, photovoltaics, catalysis, energy storage, and conversion. The possible pathways for silicon dioxide (SiO2) ALD using silicon tetrachloride (SiCl4) and water (H2O) without a catalyst have been investigated by means of density functional theory calculations. The results show that the SiCl4 half-reaction is a rate-determining step of SiO2 ALD. It may proceed through a stepwise pathway, first forming a Si-O bond and then breaking Si-Cl/O-H bonds and forming a H-Cl bond. The H2O half-reaction may undergo hydrolysis and condensation processes, which are similar to conventional SiO2 chemical vapor deposition (CVD). In the H2O half-reaction, there are massive H2O molecules adsorbed on the surface, which can result in H2O-assisted hydrolysis of the Cl-terminated surface and accelerate the H2O half-reaction. These findings may be used to improve methods for the preparation of SiO2 ALD and H2O-based ALD of other oxides, such as Al2O3, TiO2, ZrO2, and HfO2.

  6. Process for electroless deposition of metals on zirconium materials

    Science.gov (United States)

    Donaghy, Robert E.

    1978-01-01

    A process for the electroless deposition of a metal layer on an article comprised of zirconium or a zirconium alloy is disclosed. The article is activated in an aged aqueous solution comprising from about 10 to about 20 grams per liter ammonium bifluoride and from about 0.75 to about 2 grams per liter of sulfuric acid. The solution is aged by immersion of pickled zirconium in the solution for at least about 10 minutes. The loosely adhering film formed on the article in the activating step is removed and the article is contacted with an electroless plating solution containing the metal to be deposited on the article upon sufficient contact with the article.

  7. Process for electrolytic deposition of metals on zirconium materials

    Science.gov (United States)

    Donaghy, Robert E.

    1979-01-30

    A process for the electrolytic deposition of a metal layer on an article comprised of zirconium or a zirconium alloy is disclosed. The article is activated in an aged aqueous solution comprising from about 10 to about 20 grams per liter ammonium bifluoride and from about 0.75 to about 2 grams per liter of sulfuric acid. The solution is aged by immersion of pickled zirconium in the solution for at least about 10 minutes. The loosely adhering film formed on the article in the activating step is removed and the article is contacted with an electrolytic plating solution containing the metal to be deposited on the article in the presence of an electrode receiving current.

  8. Quantum confinement in amorphous TiO(2) films studied via atomic layer deposition.

    Science.gov (United States)

    King, David M; Du, Xiaohua; Cavanagh, Andrew S; Weimer, Alan W

    2008-11-05

    Despite the significant recent increase in quantum-based optoelectronics device research, few deposition techniques can reliably create the required functional nanoscale systems. Atomic layer deposition (ALD) was used here to study the quantum effects attainable through the use of this ångström-level controlled growth process. Size-dependent quantum confinement has been demonstrated using TiO(2) layers of nanoscale thickness applied to the surfaces of silicon wafers. TiO(2) films were deposited at 100 °C using TiCl(4) and H(2)O(2) in a viscous flow ALD reactor, at a rate of 0.61 Å/cycle. The low-temperature process was utilized to guarantee the amorphous deposition of TiO(2) layers and post-deposition thermal annealing was employed to promote crystallite-size modification. Hydrogen peroxide significantly reduced the residual chlorine that remained from a typical TiCl(4)-H(2)O ALD process at this temperature, down to 1.6%. Spectroscopic ellipsometry was used to quantify the optical properties both below and above the bandgap energy. A central composite design was employed to map the surface response of the film thickness-dependent bandgap shift for the as-deposited case and up to a thermal annealing temperature of 550 °C. The Brus model was used to develop a correlation between the amorphous TiO(2) film thickness and the quantum length to promote equivalent bandgap shifts.

  9. Atomic-layer deposition of silicon nitride

    CERN Document Server

    Yokoyama, S; Ooba, K

    1999-01-01

    Atomic-layer deposition (ALD) of silicon nitride has been investigated by means of plasma ALD in which a NH sub 3 plasma is used, catalytic ALD in which NH sub 3 is dissociated by thermal catalytic reaction on a W filament, and temperature-controlled ALD in which only a thermal reaction on the substrate is employed. The NH sub 3 and the silicon source gases (SiH sub 2 Cl sub 2 or SiCl sub 4) were alternately supplied. For all these methods, the film thickness per cycle was saturated at a certain value for a wide range of deposition conditions. In the catalytic ALD, the selective deposition of silicon nitride on hydrogen-terminated Si was achieved, but, it was limited to only a thin (2SiO (evaporative).

  10. Thermal and plasma enhanced atomic layer deposition of SiO{sub 2} using commercial silicon precursors

    Energy Technology Data Exchange (ETDEWEB)

    Putkonen, Matti, E-mail: matti.putkonen@vtt.fi [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, Espoo (Finland); Laboratory of Inorganic Chemistry, Aalto University School of Chemical Technology, P.O. Box 16100, FI-00076, Espoo (Finland); Bosund, Markus [Beneq Oy, Ensimmäinen savu, FI-01510, Vantaa (Finland); Ylivaara, Oili M.E.; Puurunen, Riikka L.; Kilpi, Lauri; Ronkainen, Helena [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, Espoo (Finland); Sintonen, Sakari; Ali, Saima; Lipsanen, Harri [Aalto University School of Electrical Engineering, Department of Micro- and Nanosciences, P.O. Box 13500, FI-00076 Espoo (Finland); Liu, Xuwen; Haimi, Eero; Hannula, Simo-Pekka [Aalto University School of Chemical Technology, Department of Materials Science and Engineering, P.O. Box 16200, FI-00076 Espoo (Finland); Sajavaara, Timo [University of Jyväskylä, Department of Physics, P.O. Box 35, FI-40014 Jyväskylä (Finland); Buchanan, Iain; Karwacki, Eugene [Air Products and Chemicals Inc., 7201 Hamilton Blvd., Allentown, PA 18195 (United States); Vähä-Nissi, Mika [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, Espoo (Finland)

    2014-05-02

    In this paper, we report ALD deposition of silicon dioxide using either thermal or plasma enhanced atomic layer deposition (PEALD). Several aminosilanes with differing structures and reactivity were used as silicon precursors in R and D single wafer ALD tools. One of the precursors was also tested on pilot scale batch ALD using O{sub 3} as oxidant and with substrates measuring 150 × 400 mm. The SiO{sub 2} film deposition rate was greatly dependent on the precursors used, highest values being 1.5–2.0 Å/cycle at 30–200 °C for one precursor with an O{sub 2} plasma. According to time-of-flight-elastic recoil detection analysis measurements carbon and nitrogen impurities were relatively low, but hydrogen content increased at low deposition temperatures. - Highlights: • SiO{sub 2} thin film is deposited by thermal and plasma enhanced atomic layer deposition (PEALD). • We report low-temperature deposition of SiO{sub 2} even at 30 °C by PEALD. • Scaling up of the atomic layer deposition processes to industrial batch is reported. • Deposited films had low low compressive residual stress and good conformality.

  11. Research on the processing experiments of laser metal deposition shaping

    Science.gov (United States)

    Zhang, Kai; Liu, Weijun; Shang, Xiaofeng

    2007-04-01

    Laser additive direct deposition of metals is a new rapid manufacturing technology, which combines with computer-aided design (CAD), laser cladding and rapid prototyping. The advanced technology can build fully dense metal components directly from CAD files with neither mould nor tool. Based on the theory of this technology, a promising rapid manufacturing system called "Laser Metal Deposition Shaping (LMDS)" has been constructed and developed successfully by Chinese Academy of Sciences, Shenyang Institute of Automation. Through the LMDS system, comprehensive experiments are carried out with nickel-based superalloy to systematically investigate the influences of the processing parameters on forming characteristics. By adjusting to the optimal processing parameters, fully dense and near-net-shaped metallic parts can be directly obtained through melting coaxially fed powder with a laser. Moreover, the microstructure and mechanical properties of as-formed samples are tested and analyzed synthetically. As a result, significant processing flexibility with the LMDS system over conventional processing capabilities is recognized, with potentially lower production cost, higher quality components, and shorter lead-time.

  12. Design and implementation of a novel portable atomic layer deposition/chemical vapor deposition hybrid reactor.

    Science.gov (United States)

    Selvaraj, Sathees Kannan; Jursich, Gregory; Takoudis, Christos G

    2013-09-01

    We report the development of a novel portable atomic layer deposition chemical vapor deposition (ALD/CVD) hybrid reactor setup. Unique feature of this reactor is the use of ALD/CVD mode in a single portable deposition system to fabricate multi-layer thin films over a broad range from "bulk-like" multi-micrometer to nanometer atomic dimensions. The precursor delivery system and control-architecture are designed so that continuous reactant flows for CVD and cyclic pulsating flows for ALD mode are facilitated. A custom-written LabVIEW program controls the valve sequencing to allow synthesis of different kinds of film structures under either ALD or CVD mode or both. The entire reactor setup weighs less than 40 lb and has a relatively small footprint of 8 × 9 in., making it compact and easy for transportation. The reactor is tested in the ALD mode with titanium oxide (TiO2) ALD using tetrakis(diethylamino)titanium and water vapor. The resulting growth rate of 0.04 nm/cycle and purity of the films are in good agreement with literature values. The ALD/CVD hybrid mode is demonstrated with ALD of TiO2 and CVD of tin oxide (SnOx). Transmission electron microscopy images of the resulting films confirm the formation of successive distinct TiO2-ALD and SnO(x)-CVD layers.

  13. Design and implementation of a novel portable atomic layer deposition/chemical vapor deposition hybrid reactor

    Science.gov (United States)

    Selvaraj, Sathees Kannan; Jursich, Gregory; Takoudis, Christos G.

    2013-09-01

    We report the development of a novel portable atomic layer deposition chemical vapor deposition (ALD/CVD) hybrid reactor setup. Unique feature of this reactor is the use of ALD/CVD mode in a single portable deposition system to fabricate multi-layer thin films over a broad range from "bulk-like" multi-micrometer to nanometer atomic dimensions. The precursor delivery system and control-architecture are designed so that continuous reactant flows for CVD and cyclic pulsating flows for ALD mode are facilitated. A custom-written LabVIEW program controls the valve sequencing to allow synthesis of different kinds of film structures under either ALD or CVD mode or both. The entire reactor setup weighs less than 40 lb and has a relatively small footprint of 8 × 9 in., making it compact and easy for transportation. The reactor is tested in the ALD mode with titanium oxide (TiO2) ALD using tetrakis(diethylamino)titanium and water vapor. The resulting growth rate of 0.04 nm/cycle and purity of the films are in good agreement with literature values. The ALD/CVD hybrid mode is demonstrated with ALD of TiO2 and CVD of tin oxide (SnOx). Transmission electron microscopy images of the resulting films confirm the formation of successive distinct TiO2-ALD and SnOx-CVD layers.

  14. Optical emission spectroscopy study on deposition process of microcrystalline silicon

    Institute of Scientific and Technical Information of China (English)

    Wu Zhi-Meng; Lei Qing-Song; Geng Xin-Hua; Zhao Ying; Sun Jian; Xi Jian-Ping

    2006-01-01

    This paper reports that the optical emission spectroscopy (OES) is used to monitor the plasma during the deposition process of hydrogenated microcrystalline silicon films in a very high frequency plasma enhanced chemical vapour deposition system. The OES intensities (SiH*, H*α and H*β) are investigated by varying the deposition parameters. The result shows that the discharge power, silane concentrations and substrate temperature affect the OES intensities. When the discharge power at silane concentration of 4% increases, the OES intensities increase first and then are constant, the intensities increase with the discharge power monotonously at silane concentration of 6%. The SiH* intensity increases with silane concentration, while the intensities of H*α and H*β increase first and then decrease. When the substrate temperature increases, the SiH* intensity decreases and the intensities of H*α and H*β are constant. The correlation between the intensity ratio of IH*α/ISiH* and the crystalline volume fraction (Xc) of films is confirmed.

  15. Kinetic study on hot-wire-assisted atomic layer deposition of nickel thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Guangjie, E-mail: ygjhzh@dpe.mm.t.u-tokyo.ac.jp; Shimizu, Hideharu; Momose, Takeshi; Shimogaki, Yukihiro [Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2014-01-15

    High-purity Ni films were deposited using hot-wire-assisted atomic layer deposition (HW-ALD) at deposition temperatures of 175, 250, and 350 °C. Negligible amount of nitrogen or carbon contamination was detected, even though the authors used NH{sub 2} radical as the reducing agent and nickelocene as the precursor. NH{sub 2} radicals were generated by the thermal decomposition of NH{sub 3} with the assist of HW and used to reduce the adsorbed metal growth precursors. To understand and improve the deposition process, the kinetics of HW-ALD were analyzed using a Langmuir-type model. Unlike remote-plasma-enhanced atomic layer deposition, HW-ALD does not lead to plasma-induced damage. This is a significant advantage, because the authors can supply sufficient NH{sub 2} radicals to deposit high-purity metallic films by adjusting the distance between the hot wire and the substrate. NH{sub 2} radicals have a short lifetime, and it was important to use a short distance between the radical generation site and substrate. Furthermore, the impurity content of the nickel films was independent of the deposition temperature, which is evidence of the temperature-independent nature of the NH{sub 2} radical flux and the reactivity of the NH{sub 2} radicals.

  16. Mobile setup for synchrotron based in situ characterization during thermal and plasma-enhanced atomic layer deposition

    Science.gov (United States)

    Dendooven, Jolien; Solano, Eduardo; Minjauw, Matthias M.; Van de Kerckhove, Kevin; Coati, Alessandro; Fonda, Emiliano; Portale, Giuseppe; Garreau, Yves; Detavernier, Christophe

    2016-11-01

    We report the design of a mobile setup for synchrotron based in situ studies during atomic layer processing. The system was designed to facilitate in situ grazing incidence small angle x-ray scattering (GISAXS), x-ray fluorescence (XRF), and x-ray absorption spectroscopy measurements at synchrotron facilities. The setup consists of a compact high vacuum pump-type reactor for atomic layer deposition (ALD). The presence of a remote radio frequency plasma source enables in situ experiments during both thermal as well as plasma-enhanced ALD. The system has been successfully installed at different beam line end stations at the European Synchrotron Radiation Facility and SOLEIL synchrotrons. Examples are discussed of in situ GISAXS and XRF measurements during thermal and plasma-enhanced ALD growth of ruthenium from RuO4 (ToRuS™, Air Liquide) and H2 or H2 plasma, providing insights in the nucleation behavior of these processes.

  17. Atomic layer deposition for fabrication of HfO2/Al2O3 thin films with high laser-induced damage thresholds.

    Science.gov (United States)

    Wei, Yaowei; Pan, Feng; Zhang, Qinghua; Ma, Ping

    2015-01-01

    Previous research on the laser damage resistance of thin films deposited by atomic layer deposition (ALD) is rare. In this work, the ALD process for thin film generation was investigated using different process parameters such as various precursor types and pulse duration. The laser-induced damage threshold (LIDT) was measured as a key property for thin films used as laser system components. Reasons for film damaged were also investigated. The LIDTs for thin films deposited by improved process parameters reached a higher level than previously measured. Specifically, the LIDT of the Al2O3 thin film reached 40 J/cm(2). The LIDT of the HfO2/Al2O3 anti-reflector film reached 18 J/cm(2), the highest value reported for ALD single and anti-reflect films. In addition, it was shown that the LIDT could be improved by further altering the process parameters. All results show that ALD is an effective film deposition technique for fabrication of thin film components for high-power laser systems.

  18. Atomic layer deposition of NiO hole-transporting layers for polymer solar cells.

    Science.gov (United States)

    Hsu, Che-Chen; Su, Heng-Wei; Hou, Cheng-Hung; Shyue, Jing-Jong; Tsai, Feng-Yu

    2015-09-25

    NiO is an attractive hole-transporting material for polymer solar cells (PSCs) owing to its excellent stability and electrical/optical properties. This study demonstrates, for the first time, fabrication of uniform, defect-free, and conformal NiO ultra-thin films for use as hole-transporting layers (HTLs) in PSCs by atomic layer deposition (ALD) through optimization of the ALD processing parameters. The morphological, optical, and electrical properties of ALD NiO films were determined to be favorable for their HTL application. As a result, PSCs containing an ALD NiO HTL with an optimized thickness of 4 nm achieved a power conversion efficiency (PCE) of 3.4%, which was comparable to that of a control device with a poly(3,4-ethylenedioxy-thiophene):poly(styrene-sulfonate) HTL. The high quality and manufacturing scalability of ALD NiO films demonstrated here will facilitate the adoption of NiO HTLs in PSCs.

  19. A review of atomic layer deposition providing high performance lithium sulfur batteries

    Science.gov (United States)

    Yan, Bo; Li, Xifei; Bai, Zhimin; Song, Xiaosheng; Xiong, Dongbin; Zhao, Mengli; Li, Dejun; Lu, Shigang

    2017-01-01

    With the significant obstacles that have been conquered in lithium-sulfur (Li-S) batteries, it is urgent to impel accelerating development of room-temperature Li-S batteries with high energy density and long-term stability. In view of the unique solid-liquid-solid conversion processes of Li-S batteries, however, designing effective strategies to address the insulativity and volume effect of cathode, shuttle of soluble polysulfides, and/or safety hazard of Li metal anode has been challenging. An atomic layer deposition (ALD) is a representative thin film technology with exceptional capabilities in developing atomic-precisely conformal films. It has been demonstrated to be a promise strategy of solving emerging issues in advanced electrical energy storage (EES) devices via the surface modification and/or the fabrication of complex nanostructured materials. In this review, the recent developments and significances on how ALD improves the performance of Li-S batteries were discussed in detail. Significant attention mainly focused on the various strategies with the use of ALD to refine the electrochemical interfaces and cell configurations. Furthermore, the novel opportunities and perspective associated with ALD for future research directions were summarized. This review may boost the development and application of advanced Li-S batteries using ALD.

  20. Atomic layer deposition of NiO hole-transporting layers for polymer solar cells

    Science.gov (United States)

    Hsu, Che-Chen; Su, Heng-Wei; Hou, Cheng-Hung; Shyue, Jing-Jong; Tsai, Feng-Yu

    2015-09-01

    NiO is an attractive hole-transporting material for polymer solar cells (PSCs) owing to its excellent stability and electrical/optical properties. This study demonstrates, for the first time, fabrication of uniform, defect-free, and conformal NiO ultra-thin films for use as hole-transporting layers (HTLs) in PSCs by atomic layer deposition (ALD) through optimization of the ALD processing parameters. The morphological, optical, and electrical properties of ALD NiO films were determined to be favorable for their HTL application. As a result, PSCs containing an ALD NiO HTL with an optimized thickness of 4 nm achieved a power conversion efficiency (PCE) of 3.4%, which was comparable to that of a control device with a poly(3,4-ethylenedioxy-thiophene):poly(styrene-sulfonate) HTL. The high quality and manufacturing scalability of ALD NiO films demonstrated here will facilitate the adoption of NiO HTLs in PSCs.

  1. Probabilistic distributions of pinhole defects in atomic layer deposited films on polymeric substrates

    Energy Technology Data Exchange (ETDEWEB)

    Yersak, Alexander S., E-mail: alexander.yersak@colorado.edu; Lee, Yung-Cheng [Department of Mechanical Engineering, University of Colorado at Boulder, 1045 Regent Drive, 422 UCB, Boulder, Colorado 80309-0422 (United States)

    2016-01-15

    Pinhole defects in atomic layer deposition (ALD) coatings were measured in an area of 30 cm{sup 2} in an ALD reactor, and these defects were represented by a probabilistic cluster model instead of a single defect density value with number of defects over area. With the probabilistic cluster model, the pinhole defects were simulated over a manufacturing scale surface area of ∼1 m{sup 2}. Large-area pinhole defect simulations were used to develop an improved and enhanced design method for ALD-based devices. A flexible thermal ground plane (FTGP) device requiring ALD hermetic coatings was used as an example. Using a single defect density value, it was determined that for an application with operation temperatures higher than 60 °C, the FTGP device would not be possible. The new probabilistic cluster model shows that up to 40.3% of the FTGP would be acceptable. With this new approach the manufacturing yield of ALD-enabled or other thin film based devices with different design configurations can be determined. It is important to guide process optimization and control and design for manufacturability.

  2. Processing Parameters Optimization for Material Deposition Efficiency in Laser Metal Deposited Titanium Alloy

    Science.gov (United States)

    Mahamood, Rasheedat M.; Akinlabi, Esther T.

    2016-03-01

    Ti6Al4V is an important Titanium alloy that is mostly used in many applications such as: aerospace, petrochemical and medicine. The excellent corrosion resistance property, the high strength to weight ratio and the retention of properties at high temperature makes them to be favoured in most applications. The high cost of Titanium and its alloys makes their use to be prohibitive in some applications. Ti6Al4V can be cladded on a less expensive material such as steel, thereby reducing cost and providing excellent properties. Laser Metal Deposition (LMD) process, an additive manufacturing process is capable of producing complex part directly from the 3-D CAD model of the part and it also has the capability of handling multiple materials. Processing parameters play an important role in LMD process and in order to achieve desired results at a minimum cost, then the processing parameters need to be properly controlled. This paper investigates the role of processing parameters: laser power, scanning speed, powder flow rate and gas flow rate, on the material utilization efficiency in laser metal deposited Ti6Al4V. A two-level full factorial design of experiment was used in this investigation, to be able to understand the processing parameters that are most significant as well as the interactions among these processing parameters. Four process parameters were used, each with upper and lower settings which results in a combination of sixteen experiments. The laser power settings used was 1.8 and 3 kW, the scanning speed was 0.05 and 0.1 m/s, the powder flow rate was 2 and 4 g/min and the gas flow rate was 2 and 4 l/min. The experiments were designed and analyzed using Design Expert 8 software. The software was used to generate the optimized process parameters which were found to be laser power of 3.2 kW, scanning speed of 0.06 m/s, powder flow rate of 2 g/min and gas flow rate of 3 l/min.

  3. Smooth germanium nanowires prepared by a hydrothermal deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Pei, L.Z., E-mail: lzpei1977@163.com [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Laboratory of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China); Zhao, H.S. [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Laboratory of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China); Tan, W. [Henkel Huawei Electronics Co. Ltd., Lian' yungang, Jiangsu 222006 (China); Yu, H.Y. [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Laboratory of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China); Chen, Y.W. [Department of Materials Science, Fudan University, Shanghai 200433 (China); Fan, C.G. [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Laboratory of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China); Zhang, Qian-Feng, E-mail: zhangqf@ahut.edu.cn [School of Materials Science and Engineering, Institute of Molecular Engineering and Applied Chemistry, Key Laboratory of Materials Science and Processing of Anhui Province, Anhui University of Technology, Ma' anshan, Anhui 243002 (China)

    2009-11-15

    Smooth germanium nanowires were prepared using Ge and GeO{sub 2} as the starting materials and Cu sheet as the substrate by a simple hydrothermal deposition process. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations show that the germanium nanowires are smooth and straight with uniform diameter of about 150 nm in average and tens of micrometers in length. X-ray diffraction (XRD) and Raman spectrum of the germanium nanowires display that the germanium nanowires are mainly composed of cubic diamond phase. PL spectrum shows a strong blue light emission at 441 nm. The growth mechanism is also discussed.

  4. Atmospheric pressure atomic layer deposition of Al₂O₃ using trimethyl aluminum and ozone.

    Science.gov (United States)

    Mousa, Moataz Bellah M; Oldham, Christopher J; Parsons, Gregory N

    2014-04-08

    High throughput spatial atomic layer deposition (ALD) often uses higher reactor pressure than typical batch processes, but the specific effects of pressure on species transport and reaction rates are not fully understood. For aluminum oxide (Al2O3) ALD, water or ozone can be used as oxygen sources, but how reaction pressure influences deposition using ozone has not previously been reported. This work describes the effect of deposition pressure, between ∼2 and 760 Torr, on ALD Al2O3 using TMA and ozone. Similar to reports for pressure dependence during TMA/water ALD, surface reaction saturation studies show self-limiting growth at low and high pressure across a reasonable temperature range. Higher pressure tends to increase the growth per cycle, especially at lower gas velocities and temperatures. However, growth saturation at high pressure requires longer O3 dose times per cycle. Results are consistent with a model of ozone decomposition kinetics versus pressure and temperature. Quartz crystal microbalance (QCM) results confirm the trends in growth rate and indicate that the surface reaction mechanisms for Al2O3 growth using ozone are similar under low and high total pressure, including expected trends in the reaction mechanism at different temperatures.

  5. Characterization of ALD grown TixAlyN and TixAlyC thin films

    Science.gov (United States)

    Kinnunen, S. A.; Malm, J.; Arstila, K.; Lahtinen, M.; Sajavaara, T.

    2017-09-01

    Atomic layer deposition (ALD) was used to grow TixAlyN and TixAlyC thin films using trimethylaluminum (TMA), titanium tetrachloride and ammonia as precursors. Deposition temperature was varied between 325 °C and 500 °C. Films were also annealed in vacuum and N2-atmosphere at 600-1000 °C. Wide range of characterization methods was used including time-of-flight elastic recoil detection analysis (ToF-ERDA), X-ray diffractometry (XRD), X-ray reflectometry (XRR), Raman spectroscopy, ellipsometry, helium ion microscopy (HIM), atomic force microscopy (AFM) and 4-point probe measurement for resistivity. Deposited films were roughly 100 nm thick and contained mainly desired elements. Carbon, chlorine and hydrogen were found to be the main impurities.

  6. Material insights of HfO2-based integrated 1-transistor-1-resistor resistive random access memory devices processed by batch atomic layer deposition

    Science.gov (United States)

    Niu, Gang; Kim, Hee-Dong; Roelofs, Robin; Perez, Eduardo; Schubert, Markus Andreas; Zaumseil, Peter; Costina, Ioan; Wenger, Christian

    2016-06-01

    With the continuous scaling of resistive random access memory (RRAM) devices, in-depth understanding of the physical mechanism and the material issues, particularly by directly studying integrated cells, become more and more important to further improve the device performances. In this work, HfO2-based integrated 1-transistor-1-resistor (1T1R) RRAM devices were processed in a standard 0.25 μm complementary-metal-oxide-semiconductor (CMOS) process line, using a batch atomic layer deposition (ALD) tool, which is particularly designed for mass production. We demonstrate a systematic study on TiN/Ti/HfO2/TiN/Si RRAM devices to correlate key material factors (nano-crystallites and carbon impurities) with the filament type resistive switching (RS) behaviours. The augmentation of the nano-crystallites density in the film increases the forming voltage of devices and its variation. Carbon residues in HfO2 films turn out to be an even more significant factor strongly impacting the RS behaviour. A relatively higher deposition temperature of 300 °C dramatically reduces the residual carbon concentration, thus leading to enhanced RS performances of devices, including lower power consumption, better endurance and higher reliability. Such thorough understanding on physical mechanism of RS and the correlation between material and device performances will facilitate the realization of high density and reliable embedded RRAM devices with low power consumption.

  7. Material insights of HfO2-based integrated 1-transistor-1-resistor resistive random access memory devices processed by batch atomic layer deposition.

    Science.gov (United States)

    Niu, Gang; Kim, Hee-Dong; Roelofs, Robin; Perez, Eduardo; Schubert, Markus Andreas; Zaumseil, Peter; Costina, Ioan; Wenger, Christian

    2016-06-17

    With the continuous scaling of resistive random access memory (RRAM) devices, in-depth understanding of the physical mechanism and the material issues, particularly by directly studying integrated cells, become more and more important to further improve the device performances. In this work, HfO2-based integrated 1-transistor-1-resistor (1T1R) RRAM devices were processed in a standard 0.25 μm complementary-metal-oxide-semiconductor (CMOS) process line, using a batch atomic layer deposition (ALD) tool, which is particularly designed for mass production. We demonstrate a systematic study on TiN/Ti/HfO2/TiN/Si RRAM devices to correlate key material factors (nano-crystallites and carbon impurities) with the filament type resistive switching (RS) behaviours. The augmentation of the nano-crystallites density in the film increases the forming voltage of devices and its variation. Carbon residues in HfO2 films turn out to be an even more significant factor strongly impacting the RS behaviour. A relatively higher deposition temperature of 300 °C dramatically reduces the residual carbon concentration, thus leading to enhanced RS performances of devices, including lower power consumption, better endurance and higher reliability. Such thorough understanding on physical mechanism of RS and the correlation between material and device performances will facilitate the realization of high density and reliable embedded RRAM devices with low power consumption.

  8. Material insights of HfO2-based integrated 1-transistor-1-resistor resistive random access memory devices processed by batch atomic layer deposition

    Science.gov (United States)

    Niu, Gang; Kim, Hee-Dong; Roelofs, Robin; Perez, Eduardo; Schubert, Markus Andreas; Zaumseil, Peter; Costina, Ioan; Wenger, Christian

    2016-01-01

    With the continuous scaling of resistive random access memory (RRAM) devices, in-depth understanding of the physical mechanism and the material issues, particularly by directly studying integrated cells, become more and more important to further improve the device performances. In this work, HfO2-based integrated 1-transistor-1-resistor (1T1R) RRAM devices were processed in a standard 0.25 μm complementary-metal-oxide-semiconductor (CMOS) process line, using a batch atomic layer deposition (ALD) tool, which is particularly designed for mass production. We demonstrate a systematic study on TiN/Ti/HfO2/TiN/Si RRAM devices to correlate key material factors (nano-crystallites and carbon impurities) with the filament type resistive switching (RS) behaviours. The augmentation of the nano-crystallites density in the film increases the forming voltage of devices and its variation. Carbon residues in HfO2 films turn out to be an even more significant factor strongly impacting the RS behaviour. A relatively higher deposition temperature of 300 °C dramatically reduces the residual carbon concentration, thus leading to enhanced RS performances of devices, including lower power consumption, better endurance and higher reliability. Such thorough understanding on physical mechanism of RS and the correlation between material and device performances will facilitate the realization of high density and reliable embedded RRAM devices with low power consumption. PMID:27312225

  9. Application of Thin ZnO ALD Layers in Fiber-Optic Fabry-Pérot Sensing Interferometers

    OpenAIRE

    Daria Majchrowicz; Marzena Hirsch; Paweł Wierzba; Michael Bechelany; Roman Viter; Małgorzata Jędrzejewska‑Szczerska

    2016-01-01

    In this paper we investigated the response of a fiber-optic Fabry-Pérot sensing interferometer with thin ZnO layers deposited on the end faces of the optical fibers forming the cavity. Standard telecommunication single-mode optical fiber (SMF-28) segments were used with the thin ZnO layers deposited by Atomic Layer Deposition (ALD). Measurements were performed with the interferometer illuminated by two broadband sources operating at 1300 nm and 1550 nm. Reflected interference signal was acqui...

  10. New process may aid solution mining. [Fracturing salt deposits

    Energy Technology Data Exchange (ETDEWEB)

    1970-12-01

    A novel approach is presented regarding fracturing salt deposits. It promises to make solution mining more eficient in recovering potash from a deep ore-body. In the process, wells to supply process water are drilled in the center of a proposed mining field. The well depth is determined by the location of a water-bearing stratum having a geothermic heat content at least equal to that in the mineral strata to be mined. If process water of lower heat content is used, it can be warmed artificially by steam injection or allowed to absorb heat in the geothermic environment prevailing in the mineral stratum during the process of curing the brine to maturity. Once a process water source is assured, injection wells are drilled to the deepest stratum of sylvinite. The water is then injected adjacent to a clay bed at a hydraulic pressure sufficient to permit breakdown of the formation. Starting at the lowest stratum permits advantage to be taken of an ascending fracture plane. After having achieved breakdown in each stratum, the operator continues injection of water to assure coverage of the necessary fractured plane. Then the brine field development wells are drilled in a convenient pattern to correspond with the direction of the fracture plane (these can be used at a later date either as brine-producing or injection wells). Well spacings are proposed (between injection wells of at least 400 ft.

  11. In-situ ALD growth of hafnium oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Karavaev, Konstantin; Tallarida, Massimo; Schmeisser, Dieter [Brandenburgische Technische Universitaet Cottbus (Germany). Angewandte Physik - Sensorik; Zschech, Ehrenfried [AMD Saxony LLC and Co. KG, Center for Complex Analysis, Dresden (Germany)

    2008-07-01

    We report on a novel system for in-situ atomic layer growth (ALD) of high-k dielectric films. First results were obtained for Hf-oxide samples by using Hf-tetrachloride as precursor and water as oxidizer. We compare the photoelectron spectra of Si 2p, O 1s and Hf 4f of our in-situ prepared films with samples (ex-situ) prepared by industrial ALD reactors and discuss similarities and differences observed in the core level spectra of the various samples by considering the different growth conditions.

  12. Reliability study of Zr and Al incorporated Hf based high-k dielectric deposited by advanced processing

    Science.gov (United States)

    Bhuyian, Md Nasir Uddin

    Hafnium-based high-kappa dielectric materials have been successfully used in the industry as a key replacement for SiO2 based gate dielectrics in order to continue CMOS device scaling to the 22-nm technology node. Further scaling according to the device roadmap requires the development of oxides with higher kappa values in order to scale the equivalent oxide thickness (EOT) to 0.7 nm or below while achieving low defect densities. In addition, next generation devices need to meet challenges like improved channel mobility, reduced gate leakage current, good control on threshold voltage, lower interface state density, and good reliability. In order to overcome these challenges, improvements of the high-kappa film properties and deposition methods are highly desirable. In this dissertation, a detail study of Zr and Al incorporated HfO 2 based high-kappa dielectrics is conducted to investigate improvement in electrical characteristics and reliability. To meet scaling requirements of the gate dielectric to sub 0.7 nm, Zr is added to HfO2 to form Hf1-xZrxO2 with x=0, 0.31 and 0.8 where the dielectric film is deposited by using various intermediate processing conditions, like (i) DADA: intermediate thermal annealing in a cyclical deposition process; (ii) DSDS: similar cyclical process with exposure to SPA Ar plasma; and (iii) As-Dep: the dielectric deposited without any intermediate step. MOSCAPs are formed with TiN metal gate and the reliability of these devices is investigated by subjecting them to a constant voltage stress in the gate injection mode. Stress induced flat-band voltage shift (DeltaVFB), stress induced leakage current (SILC) and stress induced interface state degradation are observed. DSDS samples demonstrate the superior characteristics whereas the worst degradation is observed for DADA samples. Time dependent dielectric breakdown (TDDB) shows that DSDS Hf1-xZrxO2 (x=0.8) has the superior characteristics with reduced oxygen vacancy, which is affiliated to

  13. In situ metrology to characterize water vapor delivery during atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ahmido, Tariq, E-mail: tariq.ahmido@nist.gov; Kimes, William A.; Sperling, Brent A.; Hodges, Joseph T.; Maslar, James E. [Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8320, Gaithersburg, Maryland 20899-8320 (United States)

    2016-05-15

    Water is often employed as the oxygen source in metal oxide atomic layer deposition (ALD) processes. It has been reported that variations in the amount of water delivered during metal oxide ALD can impact the oxide film properties. Hence, one contribution to optimizing metal oxide ALD processes would be to identify methods to better control water dose. The development of rapid, quantitative techniques for in situ water vapor measurements during ALD processes would be beneficial to achieve this goal. In this report, the performance of an in situ tunable diode laser absorption spectroscopy (TDLAS) scheme for performing rapid, quantitative water partial pressure measurements in a representative quarter-inch ALD delivery line is described. This implementation of TDLAS, which utilizes a near-infrared distributed-feedback diode laser and wavelength modulation spectroscopy, provides measurements of water partial pressure on a timescale comparable to or shorter than the timescale of the gas dynamics in typical ALD systems. Depending on the degree of signal averaging, this TDLAS system was capable of measuring the water partial pressure with a detection limit in the range of ∼0.80 to ∼0.08 Pa. The utility of this TDLAS scheme was demonstrated by using it to identify characteristics of a representative water delivery system that otherwise would have been difficult to predict. Those characteristics include (1) the magnitude and time dependence of the pressure transient that can occur during water injection, and (2) the dependence of the steady-state water partial pressure on the carrier gas flow rate and the setting of the water ampoule flow restriction.

  14. LDRD Project 52523 final report :Atomic layer deposition of highly conformal tribological coatings.

    Energy Technology Data Exchange (ETDEWEB)

    Jungk, John Michael (University of Minnesota); Dugger, Michael Thomas; George, Steve M. (University of Colorado); Prasad, Somuri V.; Grubbs, Robert K.; Moody, Neville Reid; Mayer, Thomas Michael; Scharf, Thomas W.; Goeke, Ronald S.; Gerberich, William W. (University of Minnesota)

    2005-10-01

    Friction and wear are major concerns in the performance and reliability of micromechanical (MEMS) devices. While a variety of lubricant and wear resistant coatings are known which we might consider for application to MEMS devices, the severe geometric constraints of many micromechanical systems (high aspect ratios, shadowed surfaces) make most deposition methods for friction and wear-resistance coatings impossible. In this program we have produced and evaluate highly conformal, tribological coatings, deposited by atomic layer deposition (ALD), for use on surface micromachined (SMM) and LIGA structures. ALD is a chemical vapor deposition process using sequential exposure of reagents and self-limiting surface chemistry, saturating at a maximum of one monolayer per exposure cycle. The self-limiting chemistry results in conformal coating of high aspect ratio structures, with monolayer precision. ALD of a wide variety of materials is possible, but there have been no studies of structural, mechanical, and tribological properties of these films. We have developed processes for depositing thin (<100 nm) conformal coatings of selected hard and lubricious films (Al2O3, ZnO, WS2, W, and W/Al{sub 2}O{sub 3} nanolaminates), and measured their chemical, physical, mechanical and tribological properties. A significant challenge in this program was to develop instrumentation and quantitative test procedures, which did not exist, for friction, wear, film/substrate adhesion, elastic properties, stress, etc., of extremely thin films and nanolaminates. New scanning probe and nanoindentation techniques have been employed along with detailed mechanics-based models to evaluate these properties at small loads characteristic of microsystem operation. We emphasize deposition processes and fundamental properties of ALD materials, however we have also evaluated applications and film performance for model SMM and LIGA devices.

  15. Relation of lifetime to surface passivation for atomic-layer-deposited Al{sub 2}O{sub 3} on crystalline silicon solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Joon [Graduate School of Energy Science and Technology, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Song, Hee Eun, E-mail: hsong@kier.re.kr [Photovoltaic Center, Korea Institute of Energy Research, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Chang, Hyo Sik, E-mail: hschang@cnu.ac.kr [Graduate School of Energy Science and Technology, Chungnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of)

    2015-03-15

    Highlights: • We investigated the relation of potassium contamination on Si solar wafer to lifetime. • We deposited Al{sub 2}O{sub 3} layer by atomic layer deposition (ALD) on Si solar wafer after several cleaning process. • Potassium can be left on Si surface by incomplete cleaning process and degrade the Al{sub 2}O{sub 3} passivation quality. - Abstract: We investigated the relation of potassium contamination on a crystalline silicon (c-Si) surface after potassium hydroxide (KOH) etching to the lifetime of the c-Si solar cell. Alkaline solution was employed for saw damage removal (SDR), texturing, and planarization of a textured c-Si solar wafer prior to atomic layer deposition (ALD) Al{sub 2}O{sub 3} growth. In the solar-cell manufacturing process, ALD Al{sub 2}O{sub 3} passivation is utilized to obtain higher conversion efficiency. ALD Al{sub 2}O{sub 3} shows excellent surface passivation, though minority carrier lifetime varies with cleaning conditions. In the present study, we investigated the relation of potassium contamination to lifetime in solar-cell processing. The results showed that the potassium-contaminated samples, due to incomplete cleaning of KOH, had a short lifetime, thus establishing that residual potassium can degrade Al{sub 2}O{sub 3} surface passivation.

  16. Effect of layer thickness setting on deposition characteristics in direct energy deposition (DED) process

    Science.gov (United States)

    Shim, Do-Sik; Baek, Gyeong-Yun; Seo, Jin-Seon; Shin, Gwang-Yong; Kim, Kee-Poong; Lee, Ki-Yong

    2016-12-01

    Direct energy deposition is an additive manufacturing technique that involves the melting of metal powder with a high-powered laser beam and is used to build a variety of components. In laser-assisted metal deposition, the mechanical and metallurgical properties achieved are influenced by many factors. This paper addresses methods for selecting an appropriate layer thickness setting, which is an important parameter in layer-by-layer deposition manufacturing. A new procedure is proposed for determining the layer thickness setting for use in slicing of a part based on the single-layer height for a given depositing condition. This procedure was compared with a conventional method that uses an empirically determined layer thickness and with a feedback control method. The micro-hardness distribution, location of the melting pool, and microstructures of the deposited layers after deposition of a simple target shape were investigated for each procedure. The experimental results show that even though the feedback control method is the most effective method for obtaining the desired geometry, the deposited region was characterized by inhomogeneity of micro-hardness due to the time-variable depositing conditions involved. The largest dimensional error was associated with the conventional deposition procedure, which produced a rise in the melting zone due to over-deposition with respect to the slicing thickness, especially at the high laser power level considered. In contrast, the proposed procedure produced a stable melting zone position during deposition, which resulted in the deposited part having reasonable dimensional accuracy and uniform micro-hardness throughout the deposited region.

  17. On model materials designed by atomic layer deposition for catalysis purposes

    OpenAIRE

    Diskus, Madeleine

    2011-01-01

    The aim of this work was to investigate the potential of model materials designed by atomic layer deposition toward applications in catalysis research. Molybdenum based catalysts promoted with cobalt were selected as target materials, considering their important roles in various industrial processes. Particular attention was paid to understand the growth dynamics of the ALD processes involved and further to characterize the obtained materials carefully. It was of main concern to verify the fe...

  18. Stable and High-Performance Flexible ZnO Thin-Film Transistors by Atomic Layer Deposition.

    Science.gov (United States)

    Lin, Yuan-Yu; Hsu, Che-Chen; Tseng, Ming-Hung; Shyue, Jing-Jong; Tsai, Feng-Yu

    2015-10-14

    Passivation is a challenging issue for the oxide thin-film transistor (TFT) technologies because it requires prolonged high-temperature annealing treatments to remedy defects produced in the process, which greatly limits its manufacturability as well as its compatibility with temperature-sensitive materials such as flexible plastic substrates. This study investigates the defect-formation mechanisms incurred by atomic layer deposition (ALD) passivation processes on ZnO TFTs, based on which we demonstrate for the first time degradation-free passivation of ZnO TFTs by a TiO2/Al2O3 nanolaminated (TAO) film deposited by a low-temperature (110 °C) ALD process. By combining the TAO passivation film with ALD dielectric and channel layers into an integrated low-temperature ALD process, we successfully fabricate flexible ZnO TFTs on plastics. Thanks to the exceptional gas-barrier property of the TAO film (water vapor transmission rate (WVTR)20 cm2 V(-1) s(-1), subthreshold swing10,000 s), air-storage (>1200 h), and bending (1.3 cm radius for 1000 times).

  19. Growth of Ge nanofilms using electrochemical atomic layer deposition, with a "bait and switch" surface-limited reaction.

    Science.gov (United States)

    Liang, Xuehai; Zhang, Qinghui; Lay, Marcus D; Stickney, John L

    2011-06-01

    Ge nanofilms were deposited from aqueous solutions using the electrochemical analog of atomic layer deposition (ALD). Direct electrodeposition of Ge from an aqueous solution is self-limited to a few monolayers, depending on the pH. This report describes an E-ALD process for the growth of Ge films from aqueous solutions. The E-ALD cycle involved inducing a Ge atomic layer to deposit on a Te atomic layer formed on Ge, via underpotential deposition (UPD). The Te atomic layer was then reductively stripped from the deposit, leaving the Ge and completing the cycle. The Te atomic layer was bait for Ge deposition, after which the Te was switched out, reduced to a soluble telluride, leaving the Ge (one "bait and switch" cycle). Deposit thickness was a linear function of the number of cycles. Raman spectra indicated formation of an amorphous Ge film, consistent with the absence of a XRD pattern. Films were more stable and homogeneous when formed on Cu substrates, than on Au, due to a larger hydrogen overpotential, and the corresponding lower tendency to form bubbles.

  20. Sub-nanometer dimensions control of core/shell nanoparticles prepared by atomic layer deposition.

    Science.gov (United States)

    Weber, M J; Verheijen, M A; Bol, A A; Kessels, W M M

    2015-03-06

    Bimetallic core/shell nanoparticles (NPs) are the subject of intense research due to their unique electronic, optical and catalytic properties. Accurate and independent control over the dimensions of both core and shell would allow for unprecedented catalytic performance. Here, we demonstrate that both core and shell dimensions of Pd/Pt core/shell nanoparticles (NPs) supported on Al2O3 substrates can be controlled at the sub-nanometer level by using a novel strategy based on atomic layer deposition (ALD). From the results it is derived that the main conditions for accurate dimension control of these core/shell NPs are: (i) a difference in surface energy between the deposited core metal and the substrate to obtain island growth; (ii) a process yielding linear growth of the NP cores with ALD cycles to obtain monodispersed NPs with a narrow size distribution; (iii) a selective ALD process for the shell metal yielding a linearly increasing thickness to obtain controllable shell growth exclusively on the cores. For Pd/Pt core/shell NPs it is found that a minimum core diameter of 1 nm exists above which the NP cores are able to catalytically dissociate the precursor molecules for shell growth. In addition, initial studies on the stability of these core/shell NPs have been carried out, and it has been demonstrated that core/shell NPs can be deposited by ALD on high aspect ratio substrates such as nanowire arrays. These achievements show therefore that ALD has significant potential for the preparation of tuneable heterogeneous catalyst systems.

  1. Diode behavior in ultra-thin low temperature ALD grown zinc-oxide on silicon

    Directory of Open Access Journals (Sweden)

    Nazek El-Atab

    2013-10-01

    Full Text Available A thin-film ZnO(n/Si(p+ heterojunction diode is demonstrated. The thin film ZnO layer is deposited by Atomic Layer Deposition (ALD at different temperatures on a p-type silicon substrate. Atomic force microscopy (AFM AC-in-Air method in addition to conductive AFM (CAFM were used for the characterization of ZnO layer and to measure the current-voltage characteristics. Forward and reverse bias n-p diode behavior with good rectification properties is achieved. The diode with ZnO grown at 80°C exhibited the highest on/off ratio with a turn-on voltage (VON ∼3.5 V. The measured breakdown voltage (VBR and electric field (EBR for this diode are 5.4 V and 3.86 MV/cm, respectively.

  2. Amorphous TiO2 Compact Layers via ALD for Planar Halide Perovskite Photovoltaics.

    Science.gov (United States)

    Kim, In Soo; Haasch, Richard T; Cao, Duyen H; Farha, Omar K; Hupp, Joseph T; Kanatzidis, Mercouri G; Martinson, Alex B F

    2016-09-21

    A low-temperature (TiO2 compact layers may pave the way to more efficient, flexible, and stable inverted perovskite halide device designs. Toward this end, we utilize low-temperature thermal atomic layer deposition (ALD) to synthesize ultrathin (12 nm) compact TiO2 underlayers for planar halide perovskite PV. Although device performance with as-deposited TiO2 films is poor, we identify room-temperature UV-O3 treatment as a route to device efficiency comparable to crystalline TiO2 thin films synthesized by higher temperature methods. We further explore the chemical, physical, and interfacial properties that might explain the improved performance through X-ray diffraction, spectroscopic ellipsometry, Raman spectroscopy, and X-ray photoelectron spectroscopy. These findings challenge our intuition about effective electron selective layers as well as point the way to a greater selection of flexible substrates and more stable inverted device designs.

  3. Atomistic kinetic Monte Carlo study of atomic layer deposition derived from density functional theory.

    Science.gov (United States)

    Shirazi, Mahdi; Elliott, Simon D

    2014-01-30

    To describe the atomic layer deposition (ALD) reactions of HfO2 from Hf(N(CH3)2)4 and H2O, a three-dimensional on-lattice kinetic Monte-Carlo model is developed. In this model, all atomistic reaction pathways in density functional theory (DFT) are implemented as reaction events on the lattice. This contains all steps, from the early stage of adsorption of each ALD precursor, kinetics of the surface protons, interaction between the remaining precursors (steric effect), influence of remaining fragments on adsorption sites (blocking), densification of each ALD precursor, migration of each ALD precursors, and cooperation between the remaining precursors to adsorb H2O (cooperative effect). The essential chemistry of the ALD reactions depends on the local environment at the surface. The coordination number and a neighbor list are used to implement the dependencies. The validity and necessity of the proposed reaction pathways are statistically established at the mesoscale. The formation of one monolayer of precursor fragments is shown at the end of the metal pulse. Adsorption and dissociation of the H2O precursor onto that layer is described, leading to the delivery of oxygen and protons to the surface during the H2O pulse. Through these processes, the remaining precursor fragments desorb from the surface, leaving the surface with bulk-like and OH-terminated HfO2, ready for the next cycle. The migration of the low coordinated remaining precursor fragments is also proposed. This process introduces a slow reordering motion (crawling) at the mesoscale, leading to the smooth and conformal thin film that is characteristic of ALD.

  4. Enhancement of surface integrity of titanium alloy with copper by means of laser metal deposition process

    CSIR Research Space (South Africa)

    Erinosho, MF

    2016-04-01

    Full Text Available The laser metal deposition process possesses the combination of metallic powder and laser beam respectively. However, these combinations create an adhesive bonding that permanently solidifies the laser-enhanced-deposited powders. Titanium alloys (Ti...

  5. ALD coating of nuclear fuel actinides materials

    Energy Technology Data Exchange (ETDEWEB)

    Yacout, A. M.; Pellin, Michael J.; Yun, Di; Billone, Mike

    2017-09-05

    The invention provides a method of forming a nuclear fuel pellet of a uranium containing fuel alternative to UO.sub.2, with the steps of obtaining a fuel form in a powdered state; coating the fuel form in a powdered state with at least one layer of a material; and sintering the powdered fuel form into a fuel pellet. Also provided is a sintered nuclear fuel pellet of a uranium containing fuel alternative to UO.sub.2, wherein the pellet is made from particles of fuel, wherein the particles of fuel are particles of a uranium containing moiety, and wherein the fuel particles are coated with at least one layer between about 1 nm to about 4 nm thick of a material using atomic layer deposition, and wherein the at least one layer of the material substantially surrounds each interfacial grain barrier after the powdered fuel form has been sintered.

  6. Characteristics of a nickel thin film and formation of nickel silicide by using remote plasma atomic layer deposition with Ni( i Pr-DAD)2

    Science.gov (United States)

    Kim, Jinho; Jang, Woochool; Park, Jingyu; Jeon, Heeyoung; Kim, Hyunjung; Yuh, Junhan; Jeon, Hyeongtag

    2015-03-01

    In this study, the characteristics of nickel thin film deposited by remote plasma atomic layer deposition (RPALD) on p-type Si substrate and formation of nickel silicide using rapid thermal annealing were determined. Bis(1,4-di-isopropyl-1,3-diazabutadienyl)nickel, Ni(iPr-DAD)2, was used as a Ni precursor and ammonia plasma was used as a reactant. This was the first attempt to deposit Ni thin film using Ni(iPr-DAD)2 as a precursor for the ALD process. The RPALD Ni film was deposited with a growth rate of around 2.2{\\AA}/cycle at 250 {\\deg}C and showed significant low resistivity of 33 {\\mu}{\\Omega}cm with a total impurity concentration of around 10 at. %.The impurities of the thin film, carbon and nitrogen, were existent by the forms of C-C and C-N in a bonding state. The impurities removal tendency was investigated by comparing of experimental conditions, namely process temperature and pressure. Nitrogen impurity was removed by thermal desorption during each ALD cycle and carbon impurity was reduced by the optimizing of the process pressure which is directly related with a mean free path of NH3 plasma. After Ni deposition, nickel silicide was formed by RTA in a vacuum ambient for 1 minute. A nickel silicide layer from ALD Ni and PVD Ni was compared at the annealing temperature from 500 to 900 {\\deg}C. NiSi from ALD Ni showed better thermal stability due to the contribution of small amounts of carbon and nitrogen in the asdeposited Ni thin film. Degradation of the silicide layer was effectively suppressed with a use of ALD Ni.

  7. In situ spectroscopic ellipsometry during atomic layer deposition of Pt, Ru and Pd

    Science.gov (United States)

    Leick, N.; Weber, J. W.; Mackus, A. J. M.; Weber, M. J.; van de Sanden, M. C. M.; Kessels, W. M. M.

    2016-03-01

    The preparation of ultra-thin platinum-group metal films, such as Pt, Ru and Pd, by atomic layer deposition (ALD) was monitored in situ using spectroscopic ellipsometry in the photon energy range of 0.75-5 eV. The metals’ dielectric function was parametrized using a ‘flexible’ Kramers-Kronig consistent dielectric function because it was able to provide accurate curve shape control over the optical response of the metals. From this dielectric function, it was possible to extract the film thickness values during the ALD process. The important ALD process parameters, such as the nucleation period and growth per cycle of Pt, Ru and Pd could be determined from the thickness evolution. In addition to process parameters, the film resistivity in particular could be extracted from the modeled dielectric function. Spectroscopic ellipsometry thereby revealed itself as a feasible and valuable technique to be used in research and development applications, as well as for process monitoring during ALD.

  8. UV/vis range photodetectors based on thin film ALD grown ZnO/Si heterojunction diodes

    Science.gov (United States)

    Alkis, Sabri; Tekcan, Burak; Nayfeh, Ammar; Kemal Okyay, Ali

    2013-10-01

    We present ultraviolet-visible (UV/vis) range photodetectors (PDs) based on thin film ZnO (n)/Si (p) heterojunction diodes. ZnO films are grown by the atomic layer deposition (ALD) technique at growth temperatures of 80, 150, 200 and 250 ° C. The fabricated ZnO (n)/Si (p) photodetectors (ZnO-Si-PDs) show good electrical rectification characteristics with ON/OFF ratios reaching up to 103. Under UV (350 nm wavelength) and visible (475 nm wavelength) light illumination, the ZnO-Si-PDs give photoresponsivity values of 30-37 mA W-1 and 74-80 mA W-1 at 0.5 V reverse bias, respectively. Photoluminescence (PL) spectra of ALD grown ZnO thin films are used to support the results.

  9. Self-assembling and self-limiting monolayer deposition

    Science.gov (United States)

    Foest, Rüdiger; Schmidt, Martin; Gargouri, Hassan

    2014-02-01

    Effects of spatial ordering of molecules on surfaces are commonly utilized to deposit ultra-thin films with a thickness of a few nm. In this review paper, several methods are discussed, that are distinguished from other thin film deposition processes by exactly these effects that lead to self-assembling and self-limiting layer growth and eventually to coatings with unique and fascinating properties and applications in micro-electronics, optics, chemistry, or biology. Traditional methods for the formation of self-assembled films of ordered organic molecules, such as the Langmuir-Blodgett technique along with thermal atomic layer deposition (ALD) of inorganic molecules are evaluated. The overview is complemented by more recent developments for the deposition of organic or hybrid films by molecular layer deposition. Particular attention is given to plasma assisted techniques, either as a preparative, supplementary step or as inherent part of the deposition as in plasma enhanced ALD or plasma assisted, repeated grafting deposition. The different methods are compared and their film formation mechanisms along with their advantages are presented from the perspective of a plasma scientist. The paper contains lists of established film compounds and a collection of the relevant literature is provided for further reading.

  10. Perovskite Thin Films via Atomic Layer Deposition

    KAUST Repository

    Sutherland, Brandon R.

    2014-10-30

    © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. (Graph Presented) A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3NH3PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm-1.

  11. Perovskite thin films via atomic layer deposition.

    Science.gov (United States)

    Sutherland, Brandon R; Hoogland, Sjoerd; Adachi, Michael M; Kanjanaboos, Pongsakorn; Wong, Chris T O; McDowell, Jeffrey J; Xu, Jixian; Voznyy, Oleksandr; Ning, Zhijun; Houtepen, Arjan J; Sargent, Edward H

    2015-01-01

    A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3 NH3 PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm(-1) .

  12. Understanding processes affecting mineral deposits in humid environments

    Science.gov (United States)

    Seal, Robert R., II; Ayuso, Robert A.

    2011-01-01

    Recent interdisciplinary studies by the U.S. Geological Survey have resulted in substantial progress toward understanding the influence that climate and hydrology have on the geochemical signatures of mineral deposits and the resulting mine wastes in the eastern United States. Specific areas of focus include the release, transport, and fate of acid, metals, and associated elements from inactive mines in temperate coastal areas and of metals from unmined mineral deposits in tropical to subtropical areas; the influence of climate, geology, and hydrology on remediation options for abandoned mines; and the application of radiogenic isotopes to uniquely apportion source contributions that distinguish natural from mining sources and extent of metal transport. The environmental effects of abandoned mines and unmined mineral deposits result from a complex interaction of a variety of chemical and physical factors. These include the geology of the mineral deposit, the hydrologic setting of the mineral deposit and associated mine wastes, the chemistry of waters interacting with the deposit and associated waste material, the engineering of a mine as it relates to the reactivity of mine wastes, and climate, which affects such factors as temperature and the amounts of precipitation and evapotranspiration; these factors, in turn, influence the environmental behavior of mineral deposits. The role of climate is becoming increasingly important in environmental investigations of mineral deposits because of the growing concerns about climate change.

  13. Atomic layer deposition of ZrO{sub 2} thin film on Si(100) using {η"5:η"1-Cp(CH_2)_3NMe}Zr(NMe{sub 2}){sub 2}/O{sub 3} as precursors

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jae-Sun, E-mail: jungjes@sbsial.com [Department of Chemistry, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Soulbrain Sigma-Aldrich Co., Ltd. 34-12, Gongju-si, Chungcheoungnam-do, 314-240 (Korea, Republic of); Lee, Sang-Kyung; Hong, Chang-Sung; Shin, Jin-Ho; Kim, Jong-Moon [Soulbrain Sigma-Aldrich Co., Ltd. 34-12, Gongju-si, Chungcheoungnam-do, 314-240 (Korea, Republic of); Kang, Jun-Gill, E-mail: jgkang@cnu.ac.kr [Department of Chemistry, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2015-08-31

    Atomic layer deposition (ALD) of ZrO{sub 2} thin films was investigated using a linked cyclopentadienyl-amido compound of zirconium, {η"5:η"1-Cp(CH_2)_3NMe}Zr(NMe{sub 2}){sub 2} with ozone. The ALD-window was established as 300–380 °C with a growth rate of about 0.95 Å/cycle. A good film conformality of 0.95 for 5.7–6.1 nm-thick film was obtained for bottom and sidewall step coverages of 0.93 and 0.95, respectively. The ALD at 330 °C yielded a ZrO{sub 2} having good crystallinity. The film showed low impurity levels and a strong tendency to form the tetragonal/cubic phases despite a low film thickness of 8.58 nm (root-mean-square roughness = 0.49 nm). Better ALD performance was obtained with this linked precursor than with the commonly used CpZr(NMe{sub 2}){sub 3} precursor. Furthermore, theoretical calculations for the ALD processes on hydroxylated Si wafer surfaces were performed by using density function theory. Initial growth mechanism of ZrO{sub 2} from CpZr(NMe{sub 2}){sub 3} and {η"5:η"1-Cp(CH_2)_3NMe}Zr(NMe{sub 2}){sub 2} were proposed on atomic-scale structure. - Highlights: • Linked and non-linked cyclopentadienyl-related Zr(IV) precursors were synthesized. • ZrO{sub 2} thin films were fabricated on Si wafer via atomic layer deposition (ALD). • The linked precursor resulted in excellent thin film, compared with the non-linked one. • Quantum mechanical calculations were performed for initial ALD growth mechanism.

  14. The stratigraphy, depositional processes, and environment of the late Pleistocene Polallie-period deposits at Mount Hood Volcano, Oregon, USA

    Science.gov (United States)

    Thouret, Jean-Claude

    2005-08-01

    The Polallie eruptive period of Mt. Hood, Oregon, is the last major episode of eruption and dome growth, before the late Holocene activity which was centered at Crater Rock. A volume of 4-8 km 3 of Polallie deposits forms an apron of ca. 60 km 2 on the east, northeast and southeast flanks. The Polallie deposits can be divided, stratigraphically, into four groups: Group I rockslide avalanche and pyroclastic-flow deposits; Group II debris-flow and pyroclastic-flow deposits that suggest some explosive activity and remobilization of pyroclastic debris in a glacial environment; Group III block-and-ash flow deposits that attest to summit dome growth; Group IV alternating debris-flow deposits, glacial sediments, and reworked pyroclastic-flow deposits that indicate a decrease in dome activity and an increase in erosion and transport. Group III clearly indicates frequent episodes of dome growth and collapse, whereas Groups II and IV imply increasing erosion and, conversely, decreasing volcanic activity. The Polallie period occurred in the late Pleistocene during and just after the last Alpine glaciation, which is named Evans Creek in the Cascade Range. According to four K-Ar age dates on lava flows interbedded with Polallie deposits and to published minimum 14C ages on tephra and soils overlying these deposits, the Polallie period had lasted 15,000-22,000 years between 28-34 ka and 12-13 ka. From stratigraphic subdivisions, sedimentary lithofacies and features and from the grain-size and geochemical data, we infer that the Polallie depositional record is a result of the interplay of several processes acting during a long-lasting period of dome growth and destruction. The growth of several domes near the present summit was intermittent, because each group of sediments encompasses primary (pyroclastic) and secondary (volcaniclastic and epiclastic) deposition. Direct deposition of primary material has occurred within intervals of erosion that have probably included meltwater

  15. Towards ALD thin film stabilized single-atom Pd1 catalysts.

    Science.gov (United States)

    Piernavieja-Hermida, Mar; Lu, Zheng; White, Anderson; Low, Ke-Bin; Wu, Tianpin; Elam, Jeffrey W; Wu, Zili; Lei, Yu

    2016-08-18

    Supported precious metal single-atom catalysts have shown interesting activity and selectivity in recent studies. However, agglomeration of these highly mobile mononuclear surface species can eliminate their unique catalytic properties. Here we study a strategy for synthesizing thin film stabilized single-atom Pd1 catalysts using atomic layer deposition (ALD). The thermal stability of the Pd1 catalysts is significantly enhanced by creating a nanocavity thin film structure. In situ infrared spectroscopy and Pd K-edge X-ray absorption spectroscopy (XAS) revealed that the Pd1 was anchored on the surface through chlorine sites. The thin film stabilized Pd1 catalysts were thermally stable under both oxidation and reduction conditions. The catalytic performance in the methanol decomposition reaction is found to depend on the thickness of protecting layers. While Pd1 catalysts showed promising activity at low temperature in a methanol decomposition reaction, 14 cycle TiO2 protected Pd1 was less active at high temperature. Pd L3 edge XAS indicated that the low reactivity compared with Pd nanoparticles is due to the strong adsorption of carbon monoxide even at 250 °C. These results clearly show that the ALD nanocavities provide a basis for future design of single-atom catalysts that are highly efficient and stable.

  16. Appropriate deposition parameters for formation of fcc Co-Ni alloy nanowires during electrochemical deposition process

    Science.gov (United States)

    Mukhtar, Aiman; Shahzad Khan, Babar; Mehmood, Tahir

    2016-12-01

    The effect of deposition potential on the crystal structure and composition of Co-Ni alloy nanowires is studied by XRD, FE-SEM and EDX. The alloy nanowires deposited at -3.2 V are metastable fcc phase Co-Ni. The alloy nanowires deposited at -1.8 V are hcp phase Co-Ni. The formation of the metastable fcc alloy nanowires can be attributed to smaller critical clusters formed at the high potential as the smaller critical clusters favor fcc structure because of the significant surface energy effect. The content of Co inside nanowires increases with increasing potential. This can be understood by the polarization curves of depositing Co and Ni nanowires, which show that the current density ratio of Ni to Co at low potential has larger value than that at high potential.

  17. Atomic layer deposition of nanostructured materials

    CERN Document Server

    Pinna, Nicola

    2012-01-01

    Atomic layer deposition, formerly called atomic layer epitaxy, was developed in the 1970s to meet the needs of producing high-quality, large-area fl at displays with perfect structure and process controllability. Nowadays, creating nanomaterials and producing nanostructures with structural perfection is an important goal for many applications in nanotechnology. As ALD is one of the important techniques which offers good control over the surface structures created, it is more and more in the focus of scientists. The book is structured in such a way to fi t both the need of the expert reader (du

  18. AAO-assisted synthesis of highly ordered, large-scale TiO2 nanowire arrays via sputtering and atomic layer deposition.

    Science.gov (United States)

    Yao, Zhao; Wang, Cong; Li, Yang; Kim, Nam-Young

    2015-01-01

    Highly ordered nanoporous anodic aluminum oxide (AAO) thin films were fabricated in oxalic acid under a constant voltage via a two-step anodization process. To investigate the high-aspect-ratio (7.5:1) filling process, both sputtering and atomic layer deposition (ALD) were used to form TiO2 nanowires. Field emission scanning electron microscopy and high-resolution transmission electron microscopy images indicated that mushroom-like TiO2 structures were sputtered onto the AAO template surface, and the ALD-coated TiO2 exhibited fine filling results and clear crystal grain boundaries. Large-scale and free-standing TiO2 nanowire arrays were liberated by selectively removing the aluminum substrate and AAO template via a wet etching process with no collapsing or agglomeration after the drying process. ALD-deposited TiO2 nanowire arrays that were 67 nm in diameter and 400 nm high were transferred from the AAO template. The ALD process enabled the rapid, simple synthesis of highly ordered TiO2 nanowire arrays with desired parameters such as diameter, density, and thickness determined using diverse AAO templates.

  19. Lahars in Java: Initiations, Dynamics, Hazard Assessment And Deposition Processes

    Directory of Open Access Journals (Sweden)

    Franck Lavigne

    2016-05-01

    Full Text Available Lahar has been applied as a general term for rapidly flowing, high-concentration, poorly sorted sediment-laden mixtures of rock debris and water (other than normal streamflow from a volcano. Lahars are one of the most destructive phenomena associated with composite volcanoes, which are dominant in Java Island. Resulting deposits of lahar are poorly sorted, massive, made up of clasts (chiefly of volcanic composition, that generally include a mud-poor matrix. The aim of this research is threefold: to discuss the initiation of lahars occurrences, their dynamics, to assess the hazard and to analyse the deposition. Lahars are either a direct result of eruptive activity or not temporally related to eruptions. Syn-eruptive lahars may result from the transformation on pyroclastic flows or debris avalanches which transform to aqueous flows (e.g. at Papandayan in November 2002; They may be also generated through lake outburst or breaching (e.g. at Kelut in 1909 or 1966, and through removal of pyroclastic debris by subsequent heavy rainstorms. Post-eruptive lahar occurs during several years after an eruption. At Merapi, lahars are commonly rain-triggered by rainfalls having an average intensity of about 40 mm in 2 hours. Most occur during the rainy season from November to April. Non-eruptive lahars are flows generated without eruptive activity, particularly in the case of a debris avalanche or a lake outburst (e.g., Kelut. A lahar may include one or more discrete flow processes and encompass a variety of rheological flow types and flow transformations. As such, lahars encompass a continuum between debris flows and hyperconcentrated flows, as observed at Merapi, Kelut and Semeru volcanoes. Debris flows, with water contents ranging from 10 to no more than about 25% weight, are non-newtonian fluids that move as fairly coherent masses in what is thought to be predominantly laminar fashion. However, the relative importance of laminar versus turbulent regime is

  20. Redeposition in plasma-assisted atomic layer deposition: Silicon nitride film quality ruled by the gas residence time

    Energy Technology Data Exchange (ETDEWEB)

    Knoops, Harm C. M., E-mail: h.c.m.knoops@tue.nl, E-mail: w.m.m.kessels@tue.nl [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Oxford Instruments Plasma Technology, North End, Bristol BS49 4AP (United Kingdom); Peuter, K. de; Kessels, W. M. M., E-mail: h.c.m.knoops@tue.nl, E-mail: w.m.m.kessels@tue.nl [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2015-07-06

    The requirements on the material properties and growth control of silicon nitride (SiN{sub x}) spacer films in transistors are becoming ever more stringent as scaling of transistor structures continues. One method to deposit high-quality films with excellent control is atomic layer deposition (ALD). However, depositing SiN{sub x} by ALD has turned out to be very challenging. In this work, it is shown that the plasma gas residence time τ is a key parameter for the deposition of SiN{sub x} by plasma-assisted ALD and that this parameter can be linked to a so-called “redeposition effect”. This previously ignored effect, which takes place during the plasma step, is the dissociation of reaction products in the plasma and the subsequent redeposition of reaction-product fragments on the surface. For SiN{sub x} ALD using SiH{sub 2}(NH{sup t}Bu){sub 2} as precursor and N{sub 2} plasma as reactant, the gas residence time τ was found to determine both SiN{sub x} film quality and the resulting growth per cycle. It is shown that redeposition can be minimized by using a short residence time resulting in high-quality films with a high wet-etch resistance (i.e., a wet-etch rate of 0.5 nm/min in buffered HF solution). Due to the fundamental nature of the redeposition effect, it is expected to play a role in many more plasma-assisted ALD processes.

  1. Dielectric Properties of Thermal and Plasma-Assisted Atomic Layer Deposited Al2O3 Thin Films

    NARCIS (Netherlands)

    Jinesh, K. B.; van Hemmen, J. L.; M. C. M. van de Sanden,; Roozeboom, F.; Klootwijk, J. H.; Besling, W. F. A.; Kessels, W. M. M.

    2011-01-01

    A comparative electrical characterization study of aluminum oxide (Al2O3) deposited by thermal and plasma-assisted atomic layer depositions (ALDs) in a single reactor is presented. Capacitance and leakage current measurements show that the Al2O3 deposited by the plasma-assisted ALD shows excellent d

  2. Atomic Layer Deposition for Coating of High Aspect Ratio TiO2 Nanotube Layers

    Science.gov (United States)

    2016-01-01

    We present an optimized approach for the deposition of Al2O3 (as a model secondary material) coating into high aspect ratio (≈180) anodic TiO2 nanotube layers using the atomic layer deposition (ALD) process. In order to study the influence of the diffusion of the Al2O3 precursors on the resulting coating thickness, ALD processes with different exposure times (i.e., 0.5, 2, 5, and 10 s) of the trimethylaluminum (TMA) precursor were performed. Uniform coating of the nanotube interiors was achieved with longer exposure times (5 and 10 s), as verified by detailed scanning electron microscopy analysis. Quartz crystal microbalance measurements were used to monitor the deposition process and its particular features due to the tube diameter gradient. Finally, theoretical calculations were performed to calculate the minimum precursor exposure time to attain uniform coating. Theoretical values on the diffusion regime matched with the experimental results and helped to obtain valuable information for further optimization of ALD coating processes. The presented approach provides a straightforward solution toward the development of many novel devices, based on a high surface area interface between TiO2 nanotubes and a secondary material (such as Al2O3). PMID:27643411

  3. Applications of atomic layer deposition in solar cells.

    Science.gov (United States)

    Niu, Wenbin; Li, Xianglin; Karuturi, Siva Krishna; Fam, Derrick Wenhui; Fan, Hongjin; Shrestha, Santosh; Wong, Lydia Helena; Tok, Alfred Iing Yoong

    2015-02-13

    Atomic layer deposition (ALD) provides a unique tool for the growth of thin films with excellent conformity and thickness control down to atomic levels. The application of ALD in energy research has received increasing attention in recent years. In this review, the versatility of ALD in solar cells will be discussed. This is specifically focused on the fabrication of nanostructured photoelectrodes, surface passivation, surface sensitization, and band-structure engineering of solar cell materials. Challenges and future directions of ALD in the applications of solar cells are also discussed.

  4. Use of plasma enhanced ALD to construct efficient interference filters for astronomy in the FUV

    Science.gov (United States)

    Scowen, Paul A.; Nemanich, Robert; Eller, Brianna; Yu, Hongbin; Mooney, Tom; Beasley, Matt

    2016-07-01

    Over the past few years the advent of atomic layer deposition (ALD) technology has opened new capabilities to the field of coatings deposition for use in optical elements. At the same time, there have been major advances in both optical designs and detector technologies that can provide orders of magnitude improvement in throughput in the far ultraviolet (FUV) and near ultraviolet (NUV) passbands. Recent review work has shown that a veritable revolution is about to happen in astronomical diagnostic work for targets ranging from protostellar and protoplanetary systems, to the intergalactic medium that feeds gas supplies for galactic star formation, and supernovae and hot gas from star forming regions that determine galaxy formation feedback. These diagnostics are rooted in access to a forest of emission and absorption lines in the ultraviolet (UV)[1], and all that prevents this advance is the lack of throughput in such systems, even in space-based conditions. We outline an approach to use a range of materials to implement stable optical layers suitable for protective overcoats with high UV reflectivity and unprecedented uniformity, and use that capability to leverage innovative ultraviolet/optical filter construction to enable astronomical science. These materials will be deposited in a multilayer format over a metal base to produce a stable construct. Specifically, we will employ the use of PEALD (plasma-enhanced atomic layer deposition) methods for the deposition and construction of reflective layers that can be used to construct unprecedented filter designs for use in the ultraviolet.

  5. Surface passivation of nano-textured fluorescent SiC by atomic layer deposited TiO2

    DEFF Research Database (Denmark)

    Lu, Weifang; Ou, Yiyu; Jokubavicius, Valdas

    2016-01-01

    Nano-textured surfaces have played a key role in optoelectronic materials to enhance the light extraction efficiency. In this work, morphology and optical properties of nano-textured SiC covered with atomic layer deposited (ALD) TiO2 were investigated. In order to obtain a high quality surface...... for TiO2 deposition, a three-step cleaning procedure was introduced after RIE etching. The morphology of anatase TiO2 indicates that the nano-textured substrate has a much higher surface nucleated grain density than a flat substrate at the beginning of the deposition process. The corresponding...... reflectance increases with TiO2 thickness due to increased surface diffuse reflection. The passivation effect of ALD TiO2 thin film on the nano-textured fluorescent 6H-SiC sample was also investigated and a PL intensity improvement of 8.05% was obtained due to the surface passivation....

  6. UV optical properties of thin film oxide layers deposited by different processes.

    Science.gov (United States)

    Pellicori, Samuel F; Martinez, Carol L

    2011-10-01

    UV optical properties of thin film layers of compound and mixed oxide materials deposited by different processes are presented. Japan Electron Optics Laboratory plasma ion assisted deposition (JEOL PIAD), electron beam with and without IAD, and pulsed DC magnetron sputtering were used. Comparisons are made with published deposition process data. Refractive indices and absorption values to as short as 145 nm were measured by spectroscopic ellipsometry (SE). Electronic interband defect states are detected that are deposition-process dependent. SE might be effective in identifying UV optical film quality, especially in defining processes and material composition beneficial for high-energy excimer laser applications and environments requiring stable optical properties.

  7. Vacuum ultraviolet photochemical selective area atomic layer deposition of Al2O3 dielectrics

    Directory of Open Access Journals (Sweden)

    P. R. Chalker

    2015-01-01

    Full Text Available We report the photochemical atomic layer deposition of Al2O3 thin films and the use of this process to achieve area-selective film deposition. A shuttered vacuum ultraviolet (VUV light source is used to excite molecular oxygen and trimethyl aluminum to deposit films at 60°C. In-situ QCM and post-deposition ellipsometric measurements both show that the deposition rate is saturative as a function of irradiation time. Selective area deposition was achieved by projecting the VUV light through a metalized magnesium fluoride photolithographic mask and the selectivity of deposition on the illuminated and masked regions of the substrate is a logarithmic function of the UV exposure time. The Al2O3 films exhibit dielectric constants of 8 – 10 at 1 MHz after forming gas annealing, similar to films deposited by conventional thermal ALD.

  8. Analysis of Fiber deposition using Automatic Image Processing Method

    Science.gov (United States)

    Belka, M.; Lizal, F.; Jedelsky, J.; Jicha, M.

    2013-04-01

    Fibers are permanent threat for a human health. They have an ability to penetrate deeper in the human lung, deposit there and cause health hazards, e.glung cancer. An experiment was carried out to gain more data about deposition of fibers. Monodisperse glass fibers were delivered into a realistic model of human airways with an inspiratory flow rate of 30 l/min. Replica included human airways from oral cavity up to seventh generation of branching. Deposited fibers were rinsed from the model and placed on nitrocellulose filters after the delivery. A new novel method was established for deposition data acquisition. The method is based on a principle of image analysis. The images were captured by high definition camera attached to a phase contrast microscope. Results of new method were compared with standard PCM method, which follows methodology NIOSH 7400, and a good match was found. The new method was found applicable for evaluation of fibers and deposition fraction and deposition efficiency were calculated afterwards.

  9. Analysis of Fiber deposition using Automatic Image Processing Method

    Directory of Open Access Journals (Sweden)

    Jicha M.

    2013-04-01

    Full Text Available Fibers are permanent threat for a human health. They have an ability to penetrate deeper in the human lung, deposit there and cause health hazards, e.glung cancer. An experiment was carried out to gain more data about deposition of fibers. Monodisperse glass fibers were delivered into a realistic model of human airways with an inspiratory flow rate of 30 l/min. Replica included human airways from oral cavity up to seventh generation of branching. Deposited fibers were rinsed from the model and placed on nitrocellulose filters after the delivery. A new novel method was established for deposition data acquisition. The method is based on a principle of image analysis. The images were captured by high definition camera attached to a phase contrast microscope. Results of new method were compared with standard PCM method, which follows methodology NIOSH 7400, and a good match was found. The new method was found applicable for evaluation of fibers and deposition fraction and deposition efficiency were calculated afterwards.

  10. Ultrathin thermoacoustic nanobridge loudspeakers from ALD on polyimide

    Science.gov (United States)

    Brown, J. J.; Moore, N. C.; Supekar, O. D.; Gertsch, J. C.; Bright, V. M.

    2016-11-01

    The recent development of low-temperature (sound production from thermoacoustic loudspeakers fabricated from suspended tungsten nanobridges formed by ALD. Additionally, this paper develops an approach to lumped-element modeling for design of thermoacoustic nanodevices and relates the near-field plane wave model of individual transducer beams to the far-field spherical wave sound pressure that can be measured with standard experimental techniques. Arrays of suspended nanobridges with 25.8 nm thickness and sizes as small as 17 μm × 2 μm have been fabricated and demonstrated to produce audible sound using the thermoacoustic effect. The nanobridges were fabricated by ALD of 6.5 nm Al2O3 and 19.3 nm tungsten on sacrificial polyimide, with ALD performed at 130 °C and patterned by standard photolithography. The maximum observed loudspeaker sound pressure level (SPL) is 104 dB, measured at 20 kHz, 9.71 W input power, and 1 cm measurement distance, providing a loudspeaker sensitivity value of ∼64.6 dB SPL/1 mW. Sound production efficiency was measured to vary proportional to frequency f 3 and was directly proportional to input power. The devices in this paper demonstrate industrially feasible nanofabrication of thermoacoustic transducers and a sound production mechanism pertinent to submicron-scale device engineering.

  11. Fabrication of 3D core-shell multiwalled carbon nanotube@RuO2 lithium-ion battery electrodes through a RuO2 atomic layer deposition process.

    Science.gov (United States)

    Gregorczyk, Keith E; Kozen, Alexander C; Chen, Xinyi; Schroeder, Marshall A; Noked, Malachi; Cao, Anyuan; Hu, Liangbing; Rubloff, Gary W

    2015-01-27

    Pushing lithium-ion battery (LIB) technology forward to its fundamental scaling limits requires the ability to create designer heterostructured materials and architectures. Atomic layer deposition (ALD) has recently been applied to advanced nanostructured energy storage devices due to the wide range of available materials, angstrom thickness control, and extreme conformality over high aspect ratio nanostructures. A class of materials referred to as conversion electrodes has recently been proposed as high capacity electrodes. RuO2 is considered an ideal conversion material due to its high combined electronic and ionic conductivity and high gravimetric capacity, and as such is an excellent material to explore the behavior of conversion electrodes at nanoscale thicknesses. We report here a fully characterized atomic layer deposition process for RuO2, electrochemical cycling data for ALD RuO2, and the application of the RuO2 to a composite carbon nanotube electrode scaffold with nucleation-controlled RuO2 growth. A growth rate of 0.4 Å/cycle is found between ∼ 210-240 °C. In a planar configuration, the resulting RuO2 films show high first cycle electrochemical capacities of ∼ 1400 mAh/g, but the capacity rapidly degrades with charge/discharge cycling. We also fabricated core/shell MWCNT/RuO2 heterostructured 3D electrodes, which show a 50× increase in the areal capacity over their planar counterparts, with an areal lithium capacity of 1.6 mAh/cm(2).

  12. AlGaN/GaN MISHEMTs with AlN gate dielectric grown by thermal ALD technique.

    Science.gov (United States)

    Liu, Xiao-Yong; Zhao, Sheng-Xun; Zhang, Lin-Qing; Huang, Hong-Fan; Shi, Jin-Shan; Zhang, Chun-Min; Lu, Hong-Liang; Wang, Peng-Fei; Zhang, David Wei

    2015-01-01

    Recently, AlN plasma-enhanced atomic layer deposition (ALD) passivation technique had been proposed and investigated for suppressing the dynamic on-resistance degradation behavior of high-electron-mobility transistors (HEMTs). In this paper, a novel gate dielectric and passivation technique for GaN-on-Si AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MISHEMTs) is presented. This technique features the AlN thin film grown by thermal ALD at 400°C without plasma enhancement. A 10.6-nm AlN thin film was grown upon the surface of the HEMT serving as the gate dielectric under the gate electrode and as the passivation layer in the access region at the same time. The MISHEMTs with thermal ALD AlN exhibit enhanced on/off ratio, reduced channel sheet resistance, reduction of gate leakage by three orders of magnitude at a bias of 4 V, reduced threshold voltage hysteresis of 60 mV, and suppressed current collapse degradation.

  13. Atmospheric pressure plasma enhanced spatial ALD of silver

    NARCIS (Netherlands)

    Van Den Bruele, F.J.; Smets, M.; Illiberi, A.; Creyghton, Y.; Buskens, P.; Roozeboom, F.; Poodt, P.

    2014-01-01

    The authors have investigated the growth of thin silver films using a unique combination of atmospheric process elements: spatial atomic layer deposition and an atmospheric pressure surface dielectric barrier discharge plasma source. Silver films were grown on top of Si substrates with good purity a

  14. Atmospheric pressure plasma enhanced spatial ALD of silver

    NARCIS (Netherlands)

    Van Den Bruele, F.J.; Smets, M.; Illiberi, A.; Creyghton, Y.; Buskens, P.; Roozeboom, F.; Poodt, P.

    2014-01-01

    The authors have investigated the growth of thin silver films using a unique combination of atmospheric process elements: spatial atomic layer deposition and an atmospheric pressure surface dielectric barrier discharge plasma source. Silver films were grown on top of Si substrates with good purity a

  15. Atomic layer deposited TiO{sub 2} for implantable brain-chip interfacing devices

    Energy Technology Data Exchange (ETDEWEB)

    Cianci, E., E-mail: elena.cianci@mdm.imm.cnr.it [Laboratorio MDM, IMM-CNR, 20864 Agrate Brianza (MB) (Italy); Lattanzio, S. [Istituto di Fisiologia, Dipartimento di Anatomia Umana e Fisiologia, Universita di Padova, 35131 Padova (Italy); Dipartimento di Ingegneria dell' Informazione, Universita di Padova, 35131 Padova (Italy); Seguini, G. [Laboratorio MDM, IMM-CNR, 20864 Agrate Brianza (Italy); Vassanelli, S. [Istituto di Fisiologia, Dipartimento di Anatomia Umana e Fisiologia, Universita di Padova, 35131 Padova (Italy); Fanciulli, M. [Laboratorio MDM, IMM-CNR, 20864 Agrate Brianza (Italy); Dipartimento di Scienza dei Materiali, Universita degli Studi di Milano-Bicocca, 20126 Milano (Italy)

    2012-05-01

    In this paper we investigated atomic layer deposition (ALD) TiO{sub 2} thin films deposited on implantable neuro-chips based on electrolyte-oxide-semiconductor (EOS) junctions, implementing both efficient capacitive neuron-silicon coupling and biocompatibility for long-term implantable functionality. The ALD process was performed at 295 Degree-Sign C using titanium tetraisopropoxide and ozone as precursors on needle-shaped silicon substrates. Engineering of the capacitance of the EOS junctions introducing a thin Al{sub 2}O{sub 3} buffer layer between TiO{sub 2} and silicon resulted in a further increase of the specific capacitance. Biocompatibility for long-term implantable neuroprosthetic systems was checked upon in-vitro treatment.

  16. Hybrid Integrated Si/SiN Platforms for Wideband Optical Processing

    Science.gov (United States)

    2017-05-08

    through an aligned EBL, selective dry etching of the ALD oxide in F-based plasma to reach to Si pedestal, followed by an e-beam evaporation of a 500 nm...DISTRIBUTION A: Distribution approved for public release. 6 comparing plasma -enhanced chemical vapor deposition (PECVD), ALD, and hydrogen silsesquioxane (HSQ... etching processes to carve out channels of 10 μm width with 250 μm spacing from each other. As shown in Figure 1-d, by adding these "vent channels

  17. Nitrogen deposition to the United States: distribution, sources, and processes

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2012-01-01

    Full Text Available We simulate nitrogen deposition over the US in 2006–2008 by using the GEOS-Chem global chemical transport model at 1/2° × 2/3° horizontal resolution over North America and adjacent oceans. US emissions of NOx and NH3 in the model are 6.7 and 2.9 Tg N a−1 respectively, including a 20% natural contribution for each. Ammonia emissions are a factor of 3 lower in winter than summer, providing a good match to US network observations of NHx (≡NH3 gas + ammonium aerosol and ammonium wet deposition fluxes. Model comparisons to observed deposition fluxes and surface air concentrations of oxidized nitrogen species (NOy show overall good agreement but excessive wintertime HNO3 production over the US Midwest and Northeast. This suggests a model overestimate N2O5 hydrolysis in aerosols, and a possible factor is inhibition by aerosol nitrate. Model results indicate a total nitrogen deposition flux of 6.5 Tg N a−1 over the contiguous US, including 4.2 as NOy and 2.3 as NHx. Domestic anthropogenic, foreign anthropogenic, and natural sources contribute respectively 78%, 6%, and 16% of total nitrogen deposition over the contiguous US in the model. The domestic anthropogenic contribution generally exceeds 70% in the east and in populated areas of the west, and is typically 50–70% in remote areas of the west. Total nitrogen deposition in the model exceeds 10 kg N ha−1 a−1 over 35% of the contiguous US.

  18. Nitrogen deposition to the United States: distribution, sources, and processes

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2012-05-01

    Full Text Available We simulate nitrogen deposition over the US in 2006–2008 by using the GEOS-Chem global chemical transport model at 1/2°×2/3° horizontal resolution over North America and adjacent oceans. US emissions of NOx and NH3 in the model are 6.7 and 2.9 Tg N a−1 respectively, including a 20% natural contribution for each. Ammonia emissions are a factor of 3 lower in winter than summer, providing a good match to US network observations of NHx (≡NH3 gas + ammonium aerosol and ammonium wet deposition fluxes. Model comparisons to observed deposition fluxes and surface air concentrations of oxidized nitrogen species (NOy show overall good agreement but excessive wintertime HNO3 production over the US Midwest and Northeast. This suggests a model overestimate N2O5 hydrolysis in aerosols, and a possible factor is inhibition by aerosol nitrate. Model results indicate a total nitrogen deposition flux of 6.5 Tg N a−1 over the contiguous US, including 4.2 as NOy and 2.3 as NHx. Domestic anthropogenic, foreign anthropogenic, and natural sources contribute respectively 78%, 6%, and 16% of total nitrogen deposition over the contiguous US in the model. The domestic anthropogenic contribution generally exceeds 70% in the east and in populated areas of the west, and is typically 50–70% in remote areas of the west. Total nitrogen deposition in the model exceeds 10 kg N ha−1 a−1 over 35% of the contiguous US.

  19. The adsorptive-kinetic model of in-situ phosphorus doped film polysilicon deposition process

    Directory of Open Access Journals (Sweden)

    Nalivaiko O. Yu.

    2009-11-01

    Full Text Available The investigation of deposition kinetics of in-situ phosphorus doped polysilicon films has been performed. The adsorptive-kinetic model of in-situ phosphorus doped polysilicon deposition has been developed. The values of heterogeneous reaction constants and constants, which describe the desorption process for monosilane and phosphine, have been defined. The optimal process conditions, which provide the acceptable deposition rate, thickness uniformity, high doping level and conformal step coverage, have been founded.

  20. Processing Research on Chemically Vapor Deposited Silicon Nitride.

    Science.gov (United States)

    1979-12-01

    7 A-A79 328 GENERAL ELECTR IC Co PHILADELPH IA PA RE-ENTRY AND ENV--ETC F/S 3/ PROCESING RESEARCH ON CHEMICALLY VAPR DEPOSITED SILICON HITRI ETCIU) I...NH)2] x-- .Si3N 4 as well as NH 3 2) 3SiCI + 6H --- 3i + 6 HC - Si N 4 2 (V,l1) 3 4 pressure may play a part in shifting the deposition sequence from...hot-wall reactor should be further refined with em- phasis on the formation of figured geometries (hemispherical and ogive shells). As part of this

  1. Properties of slow traps of ALD Al{sub 2}O{sub 3}/GeO{sub x}/Ge nMOSFETs with plasma post oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Ke, M., E-mail: kiramn@mosfet.t.u-tokyo.ac.jp; Yu, X.; Chang, C.; Takenaka, M.; Takagi, S. [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan and JST-CREST, K' s Gobancho 6F, 7 Gobancho, Chiyoda-ku, Tokyo 102-0076 (Japan)

    2016-07-18

    The realization of Ge gate stacks with a small amount of slow trap density as well as thin equivalent oxide thickness and low interface state density (D{sub it}) is a crucial issue for Ge CMOS. In this study, we examine the properties of slow traps, particularly the location of slow traps, of Al{sub 2}O{sub 3}/GeO{sub x}/n-Ge and HfO{sub 2}/Al{sub 2}O{sub 3}/GeO{sub x}/n-Ge MOS interfaces with changing the process and structural parameters, formed by atomic layer deposition (ALD) of Al{sub 2}O{sub 3} and HfO{sub 2}/Al{sub 2}O{sub 3} combined with plasma post oxidation. It is found that the slow traps can locate in the GeO{sub x} interfacial layer, not in the ALD Al{sub 2}O{sub 3} layer. Furthermore, we study the time dependence of channel currents in the Ge n-MOSFETs with 5-nm-thick Al{sub 2}O{sub 3}/GeO{sub x}/Ge gate stacks, with changing the thickness of GeO{sub x}, in order to further clarify the position of slow traps. The time dependence of the current drift and the effective time constant of slow traps do not change among the MOSFETs with the different thickness GeO{sub x}, demonstrating that the slow traps mainly exist near the interfaces between Ge and GeO{sub x}.

  2. Plasma-Assisted ALD of an Al2O3 Permeation Barrier Layer on Plastic

    Institute of Scientific and Technical Information of China (English)

    雷雯雯; 李兴存; 陈强; 王正铎

    2012-01-01

    Atomic layer deposition (ALD) technique is used in the preparation of organic/inorganic layers, which requires uniform surfaces with their thickness down to several nanometers. For film with such thickness, the growth mode defined as the arrangement of clusters on the surface during the growth is of significance. In this work, Al2O3 thin film was deposited on various interfacial species of pre-treated polyethylene terephthalate (PET, 12 μm) by plasma assisted atomic layer deposition (PA-ALD), where trimethyl aluminium was used as the Al precursor and O2 as the oxygen source. The interracial species, -NH3, -OH, and -COOH as well as SiCHO (derived from monomer of HMDSO plasma), were grafted previously by plasma and chemical treatments. The growth mode of PA-ALD Al2O3 was then investigated in detail by combining results from in-situ diagnosis of spectroscopic ellipsometry (SE) and ex-situ characterization of as-deposited layers from the morphologies scanned by atomic force microscopy (AFM). In addition, the oxygen transmission rates (OTR) of the original and treated plastic films were measured. The possible reasons for the dependence of the OTR values on the surface species were explored.

  3. Physisorbed-precursor-assisted atomic layer deposition of reliable ultrathin dielectric films on inert graphene surfaces for low-power electronics

    Science.gov (United States)

    Jeong, Seong-Jun; Kim, Hyo Won; Heo, Jinseong; Lee, Min-Hyun; Song, Hyun Jae; Ku, JiYeon; Lee, Yunseong; Cho, Yeonchoo; Jeon, Woojin; Suh, Hwansoo; Hwang, Sungwoo; Park, Seongjun

    2016-09-01

    Among the most fundamental challenges encountered in the successful incorporation of graphene in silicon-based electronics is the conformal growth of ultrathin dielectric films, especially those with thicknesses lower than 5 nm, on chemically inert graphene surfaces. Here, we present physisorbed-precursor-assisted atomic layer deposition (pALD) as an extremely robust method for fabricating such films. Using atomic-scale characterisation, it is confirmed that conformal and intact ultrathin Al2O3 films can be synthesised on graphene by pALD. The mechanism underlying the pALD process is identified through first-principles calculations based on density functional theory. Further, this novel deposition technique is used to fabricate two types of wafer-scale devices. It is found that the incorporation of a 5 nm-thick pALD Al2O3 gate dielectric film improves the performance of metal-oxide-graphene field-effect transistors to a greater extent than does the incorporation of a conventional ALD Al2O3 film. We also employ a 5 nm-thick pALD HfO2 film as a highly scalable dielectric layer with a capacitance equivalent oxide thickness of 1 nm in graphene-based tunnelling field-effect transistors fabricated on a glass wafer and achieve a subthreshold swing of 30 mV/dec. This significant improvement in switching allows for the low-voltage operation of an inverter within 0.5 V of both the drain and the gate voltages, thus paving the way for low-power electronics.

  4. Atomic layer deposition grown MO{sub x} thin films for solar water splitting: Prospects and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Trilok; Lehnen, Thomas; Leuning, Tessa; Mathur, Sanjay, E-mail: sanjay.mathur@uni-koeln.de [Institute of Inorganic Chemistry, University of Cologne, Greinstrasse 6, D-50939 Cologne (Germany)

    2015-01-15

    The magnitude of energy challenge not only calls for efficient devices but also for abundant, inexpensive, and stable photoactive materials that can enable efficient light harvesting, charge separation and collection, as well as chemical transformations. Photoelectrochemical systems based on semiconductor materials have the possibility to transform solar energy directly into chemical energy the so-called “solar hydrogen.” The current challenge lies in the harvesting of a larger fraction of electromagnetic spectrum by enhancing the absorbance of electrode materials. In this context, atomically precise thin films of metal oxide semiconductors and their multilayered junctions are promising candidates to integrate high surface areas with well-defined electrode–substrate interface. Given its self-limited growth mechanism, the atomic layer deposition (ALD) technique offers a wide range of capabilities to deposit and modify materials at the nanoscale. In addition, it opens new frontiers for developing precursor chemistry that is inevitable to design new processes. Herein, the authors review the properties and potential of metal oxide thin films deposited by ALD for their application in photoelectrochemical water splitting application. The first part of the review covers the basics of ALD processes followed by a brief discussion on the electrochemistry of water splitting reaction. The second part focuses on different MO{sub x} films deposited by atomic layer deposition for water splitting applications; in this section, The authors discuss the most explored MO{sub x} semiconductors, namely, Fe{sub 2}O{sub 3}, TiO{sub 2}, WO{sub 3}, and ZnO, as active materials and refer to their application as protective coatings, conductive scaffolds, or in heterojunctions. The third part deals with the current challenges and future prospects of ALD processed MO{sub x} thin films for water splitting reactions.

  5. Capacitance and conductance versus voltage characterization of Al{sub 2}O{sub 3} layers prepared by plasma enhanced atomic layer deposition at 25 °C≤ T ≤ 200 °C

    Energy Technology Data Exchange (ETDEWEB)

    Henkel, Karsten, E-mail: henkel@tu-cottbus.de; Tallarida, Massimo; Schmeißer, Dieter [Applied Physics and Sensors, Brandenburg University of Technology Cottbus-Senftenberg, K.-Wachsmann-Allee 17, D-03046 Cottbus (Germany); Gargouri, Hassan; Gruska, Bernd; Arens, Michael [Sentech Instruments GmbH, Schwarzschildstraße 2, 12489 Berlin (Germany)

    2014-01-15

    In this work, plasma enhanced atomic layer deposited (PE-ALD) samples were prepared at substrate temperatures in the range between room temperature (RT) and 200 °C and investigated by capacitance–voltage and conductance–voltage recordings. The measurements are compared to standard thermal atomic layer deposition (T-ALD) at 200 °C. Very low interface state density (D{sub it}) ∼10{sup 11} eV{sup −1} cm{sup −2} could be achieved for the PE-ALD process at 200 °C substrate temperature after postdeposition anneal (PDA) in forming gas at 450 °C. The PDA works very effectively for both the PE-ALD and T-ALD at 200 °C substrate temperature delivering also similar values of negative fixed charge density (N{sub fix}) around −2.5 × 10{sup 12} cm{sup −2}. At the substrate temperature of 150 °C, highest N{sub fix} (−2.9 × 10{sup 12} cm{sup −2}) and moderate D{sub it} (2.7 × 10{sup 11} eV{sup −1} cm{sup −2}) values were observed. The as deposited PE-ALD layer at RT shows both low D{sub it} in the range of (1 to 3) × 10{sup 11} eV{sup −1} cm{sup −2} and low N{sub fix} (−4.4 × 10{sup 11} cm{sup −2}) at the same time. The dependencies of N{sub fix}, D{sub it}, and relative permittivity on the substrate temperatures and its adjustability are discussed.

  6. High Gradient Accelerator Cavities Using Atomic Layer Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ives, Robert Lawrence [Calabazas Creek Research, Inc., San Mateo, CA (United States); Parsons, Gregory [North Carolina State Univ., Raleigh, NC (United States); Williams, Philip [North Carolina State Univ., Raleigh, NC (United States); Oldham, Christopher [North Carolina State Univ., Raleigh, NC (United States); Mundy, Zach [North Carolina State Univ., Raleigh, NC (United States); Dolgashev, Valery [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2014-12-09

    In the Phase I program, Calabazas Creek Research, Inc. (CCR), in collaboration with North Carolina State University (NCSU), fabricated copper accelerator cavities and used Atomic Layer Deposition (ALD) to apply thin metal coatings of tungsten and platinum. It was hypothesized that a tungsten coating would provide a robust surface more resistant to arcing and arc damage. The platinum coating was predicted to reduce processing time by inhibiting oxides that form on copper surfaces soon after machining. Two sets of cavity parts were fabricated. One was coated with 35 nm of tungsten, and the other with approximately 10 nm of platinum. Only the platinum cavity parts could be high power tested during the Phase I program due to schedule and funding constraints. The platinum coated cavity exhibit poor performance when compared with pure copper cavities. Not only did arcing occur at lower power levels, but the processing time was actually longer. There were several issues that contributed to the poor performance. First, machining of the base copper cavity parts failed to achieve the quality and cleanliness standards specified to SLAC National Accelerator Center. Secondly, the ALD facilities were not configured to provide the high levels of cleanliness required. Finally, the nanometer coating applied was likely far too thin to provide the performance required. The coating was ablated or peeled from the surface in regions of high fields. It was concluded that the current ALD process could not provide improved performance over cavities produced at national laboratories using dedicated facilities.

  7. Low-temperature atomic layer deposition of MoO{sub x} for silicon heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Macco, B.; Vos, M.F.J.; Thissen, N.F.W.; Bol, A.A. [Department of Applied Physics, Eindhoven University of Technology, Eindhoven (Netherlands); Kessels, W.M.M. [Department of Applied Physics, Eindhoven University of Technology, Eindhoven (Netherlands); Solliance Solar Research, Eindhoven (Netherlands)

    2015-07-15

    The preparation of high-quality molybdenum oxide (MoO{sub x}) is demonstrated by plasma-enhanced atomic layer deposition (ALD) at substrate temperatures down to 50 C. The films are amorphous, slightly substoichiometric with respect to MoO{sub 3}, and free of other elements apart from hydrogen (<11 at%). The films have a high transparency in the visible region and their compatibility with a-Si:H passivation schemes is demonstrated. It is discussed that these aspects, in conjunction with the low processing temperature and the ability to deposit very thin conformal films, make this ALD process promising for the future application of MoO{sub x} in hole-selective contacts for silicon heterojunction solar cells. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Directing Hybrid Structures by Combining Self-Assembly of Functional Block Copolymers and Atomic Layer Deposition: A Demonstration on Hybrid Photovoltaics.

    Science.gov (United States)

    Moshonov, Moshe; Frey, Gitti L

    2015-11-24

    The simplicity and versatility of block copolymer self-assembly offers their use as templates for nano- and meso-structured materials. However, in most cases, the material processing requires multiple steps, and the block copolymer is a sacrificial building block. Here, we combine a self-assembled block copolymer template and atomic layer deposition (ALD) of a metal oxide to generate functional hybrid films in a simple process with no etching or burning steps. This approach is demonstrated by using the crystallization-induced self-assembly of a rod-coil block copolymer, P3HT-b-PEO, and the ALD of ZnO. The block copolymer self-assembles into fibrils, ∼ 20 nm in diameter and microns long, with crystalline P3HT cores and amorphous PEO corona. The affinity of the ALD precursors to the PEO corona directs the exclusive deposition of crystalline ZnO within the PEO domains. The obtained hybrid structure possesses the properties desired for photovoltaic films: donor-acceptor continuous nanoscale interpenetrated networks. Therefore, we integrated the films into single-layer hybrid photovoltaics devices, thus demonstrating that combining self-assembly of functional block copolymers and ALD is a simple approach to direct desired complex hybrid morphologies.

  9. Particle dry deposition to water surfaces: Processes and consequences

    DEFF Research Database (Denmark)

    Pryor, S.C.; Barthelmie, R.J.

    2000-01-01

    's oceans and seas is most significantly impacted by human activities. More than half of the world's population lives within 100 km of a coast and hence the overwhelming majority of anthropogenic fluxes to aquatic systems occur in the coastal zone. We discuss the particular challenges that arise from...... measurement requirements represent significant barriers to application to measurement of particle dry deposition fluxes although, as discussed, innovative solutions are now becoming available. In the final section, we examine meteorological controls on deposition to the coastal zone. This region of the world...... flux to coastal waters, atmosphere-surface exchange represents a significant component of the total flux and may be particularly critical during the summertime when both the riverine input and ambient nutrient concentrations are often at a minimum. In this chapter, we present an overview...

  10. Enhancing the stability of copper chromite catalysts for the selective hydrogenation of furfural with ALD overcoating (II) – Comparison between TiO2 and Al2O3 overcoatings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hongbo; Canlas, Christian; Kropf, A. Jeremy; Elam, Jeffrey W.; Dumesic, James A; Marshall, Christopher L.

    2015-01-01

    TiO2 atomic layer deposition (ALD) overcoatings were applied to copper chromite catalysts to increase the stability for 2-furfuraldehyde (“furfural”) hydrogenation. After overcoating, about 75% activity was preserved compared to neat copper chromite: much higher activity than an alumina ALD overcoated catalyst with a similar number of ALD cycles. The effects of ALD TiO2 on the active Cu nanoparticles were studied extensively using both in-situ TPR/isothermal-oxidation and in-situ furfural hydrogenation via Cu XAFS. The redox properties of Cu were modified only slightly by the TiO2 ALD overcoat. However, a subtle electronic interaction was observed between the TiO2 ALD layers and the Cu nanoparticles. With calcination at 500 °C the interaction between the TiO2 overcoat and the underlying catalyst is strong enough to inhibit migration and site blocking by chromite, but is sufficiently weaker than the interaction between the Al2O3 overcoat and copper chromite that it does not strongly inhibit the catalytic activity of the copper nanoparticles.

  11. Oxidation precursor dependence of atomic layer deposited Al2O3 films in a-Si:H(i)/Al2O3 surface passivation stacks

    Science.gov (United States)

    Xiang, Yuren; Zhou, Chunlan; Jia, Endong; Wang, Wenjing

    2015-03-01

    In order to obtain a good passivation of a silicon surface, more and more stack passivation schemes have been used in high-efficiency silicon solar cell fabrication. In this work, we prepared a-Si:H(i)/Al2O3 stacks on KOH solution-polished n-type solar grade mono-silicon(100) wafers. For the Al2O3 film deposition, both thermal atomic layer deposition (T-ALD) and plasma enhanced atomic layer deposition (PE-ALD) were used. Interface trap density spectra were obtained for Si passivation with a-Si films and a-Si:H(i)/Al2O3 stacks by a non-contact corona C-V technique. After the fabrication of a-Si:H(i)/Al2O3 stacks, the minimum interface trap density was reduced from original 3 × 1012 to 1 × 1012 cm-2 eV-1, the surface total charge density increased by nearly one order of magnitude for PE-ALD samples and about 0.4 × 1012 cm-2 for a T-ALD sample, and the carrier lifetimes increased by a factor of three (from about 10 μs to about 30 μs). Combining these results with an X-ray photoelectron spectroscopy analysis, we discussed the influence of an oxidation precursor for ALD Al2O3 deposition on Al2O3 single layers and a-Si:H(i)/Al2O3 stack surface passivation from field-effect passivation and chemical passivation perspectives. In addition, the influence of the stack fabrication process on the a-Si film structure was also discussed in this study.

  12. SnO{sub 2} thin films grown by atomic layer deposition using a novel Sn precursor

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Min-Jung [Electronic Materials Research Center, Korea Institute of Science and Technology, Seoul, 136-791 (Korea, Republic of); Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 (Korea, Republic of); Cho, Cheol Jin [Electronic Materials Research Center, Korea Institute of Science and Technology, Seoul, 136-791 (Korea, Republic of); Department of Materials Science and Engineering, Seoul National University, Seoul, 151-744 (Korea, Republic of); Kim, Kwang-Chon; Pyeon, Jung Joon [Electronic Materials Research Center, Korea Institute of Science and Technology, Seoul, 136-791 (Korea, Republic of); Park, Hyung-Ho [Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 (Korea, Republic of); Kim, Hyo-Suk; Han, Jeong Hwan; Kim, Chang Gyoun; Chung, Taek-Mo [Division of Advanced Materials, Korea Research Institute of Chemical Technology (KRICT), Daejeon, 305-600 (Korea, Republic of); Park, Tae Joo [Department of Materials Science and Engineering, Hanyang University, Ansan, 426-791 (Korea, Republic of); Kwon, Beomjin [Electronic Materials Research Center, Korea Institute of Science and Technology, Seoul, 136-791 (Korea, Republic of); Jeong, Doo Seok; Baek, Seung-Hyub [Electronic Materials Research Center, Korea Institute of Science and Technology, Seoul, 136-791 (Korea, Republic of); Department of Nanomaterials, Korea University of Science and Technology, Daejeon, 305-333 (Korea, Republic of); Kang, Chong-Yun; Kim, Jin-Sang [Electronic Materials Research Center, Korea Institute of Science and Technology, Seoul, 136-791 (Korea, Republic of); Kim, Seong Keun, E-mail: s.k.kim@kist.re.kr [Electronic Materials Research Center, Korea Institute of Science and Technology, Seoul, 136-791 (Korea, Republic of); Department of Nanomaterials, Korea University of Science and Technology, Daejeon, 305-333 (Korea, Republic of)

    2014-11-30

    Highlights: • We developed a new ALD process for SnO{sub 2} films using dimethylamino-2-methyl-2-propoxy-tin(II) as a novel Sn precursor. • The SnO{sub 2} films grown from Sn(dmamp){sub 2} has negligible impurity contents. • Sn ions in the films had a single binding state corresponding to Sn{sup 4+} in SnO{sub 2}. - Abstract: SnO{sub 2} thin films were grown by atomic layer deposition (ALD) with dimethylamino-2-methyl-2-propoxy-tin(II) (Sn(dmamp){sub 2}) and O{sub 3} in a temperature range of 100–230 °C. The ALD window was found to be in the range of 100–200 °C. The growth per cycle of the films in the ALD window increased with temperature in the range from 0.018 to 0.042 nm/cycle. Above 230 °C, the self-limiting behavior which is a unique characteristic of ALD, was not observed in the growth because of the thermal decomposition of the Sn(dmamp){sub 2} precursor. The SnO{sub 2} films were amorphous in the ALD window and exhibited quite a smooth surface. Sn ions in all films had a single binding state corresponding to Sn{sup 4+} in SnO{sub 2}. The concentration of carbon and nitrogen in the all SnO{sub 2} films was below the detection limit of the auger electron spectroscopy technique and a very small amount of carbon, nitrogen, and hydrogen was detected by secondary ions mass spectroscopy only. The impurity contents decreased with increasing the growth temperature. This is consistent with the increase in the density of the SnO{sub 2} films with respect to the growth temperature. The ALD process with Sn(dmamp){sub 2} and O{sub 3} shows excellent conformality on a hole structure with an aspect ratio of ∼9. This demonstrates that the ALD process with Sn(dmamp){sub 2} and O{sub 3} is promising for growth of robust and highly pure SnO{sub 2} films.

  13. Liquid Water- and Heat-Resistant Hybrid Perovskite Photovoltaics via an Inverted ALD Oxide Electron Extraction Layer Design.

    Science.gov (United States)

    Kim, In Soo; Cao, Duyen H; Buchholz, D Bruce; Emery, Jonathan D; Farha, Omar K; Hupp, Joseph T; Kanatzidis, Mercouri G; Martinson, Alex B F

    2016-12-14

    Despite rapid advances in conversion efficiency (>22%), the environmental stability of perovskite solar cells remains a substantial barrier to commercialization. Here, we show a significant improvement in the stability of inverted perovskite solar cells against liquid water and high operating temperature (100 °C) by integrating an ultrathin amorphous oxide electron extraction layer via atomic layer deposition (ALD). These unencapsulated inverted devices exhibit a stable operation over at least 10 h when subjected to high thermal stress (100 °C) in ambient environments, as well as upon direct contact with a droplet of water without further encapsulation.

  14. Research on chemical vapor deposition processes for advanced ceramic coatings

    Science.gov (United States)

    Rosner, Daniel E.

    1993-01-01

    Our interdisciplinary background and fundamentally-oriented studies of the laws governing multi-component chemical vapor deposition (VD), particle deposition (PD), and their interactions, put the Yale University HTCRE Laboratory in a unique position to significantly advance the 'state-of-the-art' of chemical vapor deposition (CVD) R&D. With NASA-Lewis RC financial support, we initiated a program in March of 1988 that has led to the advances described in this report (Section 2) in predicting chemical vapor transport in high temperature systems relevant to the fabrication of refractory ceramic coatings for turbine engine components. This Final Report covers our principal results and activities for the total NASA grant of $190,000. over the 4.67 year period: 1 March 1988-1 November 1992. Since our methods and the technical details are contained in the publications listed (9 Abstracts are given as Appendices) our emphasis here is on broad conclusions/implications and administrative data, including personnel, talks, interactions with industry, and some known applications of our work.

  15. Fabrication and characterization of vacuum deposited fluorescein thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jalkanen, Pasi, E-mail: pasi.jalkanen@gmail.co [University of Jyvaeskylae, Department of Physics, Nanoscience center (NSC), P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Kulju, Sampo, E-mail: sampo.j.kulju@jyu.f [University of Jyvaeskylae, Department of Physics, Nanoscience center (NSC), P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Arutyunov, Konstantin, E-mail: konstantin.arutyunov@jyu.f [University of Jyvaeskylae, Department of Physics, Nanoscience center (NSC), P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Antila, Liisa, E-mail: liisa.j.antila@jyu.f [University of Jyvaeskylae, Department of Chemistry, Nanoscience center (NSC) P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Myllyperkioe, Pasi, E-mail: pasi.myllyperkio@jyu.f [University of Jyvaeskylae, Department of Chemistry, Nanoscience center (NSC) P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Ihalainen, Teemu, E-mail: teemu.o.ihalainen@jyu.f [University of Jyvaeskylae, Department of Biology, Nanoscience center (NSC), P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Kaeaeriaeinen, Tommi, E-mail: tommi.kaariainen@lut.f [Lappeenranta University of Technology, ASTRal, P.O. Box 181, FI-50101 Mikkeli (Finland); Kaeaeriaeinen, Marja-Leena, E-mail: marja-leena.kaariainen@lut.f [Lappeenranta University of Technology, ASTRal, P.O. Box 181, FI-50101 Mikkeli (Finland); Korppi-Tommola, Jouko, E-mail: jouko.korppi-tommola@jyu.f [University of Jyvaeskylae, Department of Biology, Nanoscience center (NSC), P.O. Box 35, FI-40014 Jyvaeskylae (Finland)

    2011-03-31

    Simple vacuum evaporation technique for deposition of dyes on various solid surfaces has been developed. The method is compatible with conventional solvent-free nanofabrication processing enabling fabrication of nanoscale optoelectronic devices. Thin films of fluorescein were deposited on glass, fluorine-tin-oxide (FTO) coated glass with and without atomically layer deposited (ALD) nanocrystalline 20 nm thick anatase TiO{sub 2} coating. Surface topology, absorption and emission spectra of the films depend on their thickness and the material of supporting substrate. On a smooth glass surface the dye initially forms islands before merging into a uniform layer after 5 to 10 monolayers. On FTO covered glass the absorption spectra are similar to fluorescein solution in ethanol. Absorption spectra on ALD-TiO{sub 2} is red shifted compared to the film deposited on bare FTO. The corresponding emission spectra at {lambda} = 458 nm excitation show various thickness and substrate dependent features, while the emission of films deposited on TiO{sub 2} is quenched due to the effective electron transfer to the semiconductor conduction band.

  16. Dynamic order reduction of thin-film deposition kinetics models: A reaction factorization approach

    Energy Technology Data Exchange (ETDEWEB)

    Adomaitis, Raymond A., E-mail: adomaiti@umd.edu [Department of Chemical and Biomolecular Engineering, Institute for Systems Research, University of Maryland, College Park, Maryland 20742 (United States)

    2016-01-15

    A set of numerical tools for the analysis and dynamic dimension reduction of chemical vapor and atomic layer deposition (ALD) surface reaction models is developed in this work. The approach is based on a two-step process where in the first, the chemical species surface balance dynamic equations are factored to effectively decouple the (nonlinear) reaction rates, a process that eliminates redundant dynamic modes and that identifies conserved quantities. If successful, the second phase is implemented to factor out redundant dynamic modes when species relatively minor in concentration are omitted; if unsuccessful, the technique points to potential model structural problems. An alumina ALD process is used for an example consisting of 19 reactions and 23 surface and gas-phase species. Using the approach developed, the model is reduced by nineteen modes to a four-dimensional dynamic system without any knowledge of the reaction rate values. Results are interpreted in the context of potential model validation studies.

  17. Closed-Loop Process Control for Electron Beam Freeform Fabrication and Deposition Processes

    Science.gov (United States)

    Taminger, Karen M. (Inventor); Hafley, Robert A. (Inventor); Martin, Richard E. (Inventor); Hofmeister, William H. (Inventor)

    2013-01-01

    A closed-loop control method for an electron beam freeform fabrication (EBF(sup 3)) process includes detecting a feature of interest during the process using a sensor(s), continuously evaluating the feature of interest to determine, in real time, a change occurring therein, and automatically modifying control parameters to control the EBF(sup 3) process. An apparatus provides closed-loop control method of the process, and includes an electron gun for generating an electron beam, a wire feeder for feeding a wire toward a substrate, wherein the wire is melted and progressively deposited in layers onto the substrate, a sensor(s), and a host machine. The sensor(s) measure the feature of interest during the process, and the host machine continuously evaluates the feature of interest to determine, in real time, a change occurring therein. The host machine automatically modifies control parameters to the EBF(sup 3) apparatus to control the EBF(sup 3) process in a closed-loop manner.

  18. ALD氧化铝单层膜1064nm激光损伤特性研究%Characterization of 1 064 nm laser induced damagein ALD optical film

    Institute of Scientific and Technical Information of China (English)

    刘志超; 卫耀伟; 陈松林; 马平

    2011-01-01

    Based on Atomic Layer Deposition (ALD) technology, the single layer films were coated on fused silica and BK7 glass substrate respectively. Using small optical damage test facility, the 1064 nm laser induced damage threshold between ALD films and BK7 substrate was compared. The result shows that the ALD film damage threshold is about 10. 3 J/cm2. With the use of Nomarski microscope and Atomic Force Microscope, the morphology of damage site was discussed. The result shows that there are two kinds of damage, the peeling damage on the films and the small pits damage on substrate. The pits damage related to melting and vaporization has the depth between 70 nm and 95 nm. The damage precursors may exist in the boundary surface of ALD films and substrate.%采用原子层沉积技术(atomic layer deposition,ALD)在熔石英和BK7玻璃基底上镀制A12O3单层膜.利用小口径损伤在线测试平台对膜层的1 064 nm 激光损伤特性进行了实脸测量,获得膜层损伤阈值约为10.3 J/cm2,对比了其与BK7基底损伤阈值之间的差异;利用Nomarski显微镜和原子力显微镜分析讨论了损伤形态的特点,结果表明报伤主要表现为膜层脱落和基片小孔烧蚀,其中小孔深度集中在 70 nm~95 nm范围;讨论了损伤发生的诱因,得出膜基界面可能存在吸收源先驱的推断.

  19. Native Oxide Transport and Removal During Atomic Layer Deposition of TiO2 Films on GaAs(100) Surfaces.

    Science.gov (United States)

    Henegar, Alex J; Cook, Andrew J; Dang, Phillip; Gougousi, Theodosia

    2016-01-27

    In this work, we studied the evolution and transport of the native oxides during the atomic layer deposition (ALD) of TiO2 on GaAs(100) from tetrakis dimethyl amino titanium and H2O. Arsenic oxide transport through the TiO2 film and removal during the ALD process was investigated using transmission Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Experiments were designed to decouple these processes by utilizing their temperature dependence. A 4 nm TiO2 layer was initially deposited on a native oxide surface at 100 °C. Ex situ XPS confirmed that this step disturbed the interface minimally. An additional 3 nm TiO2 film was subsequently deposited at 150 to 250 °C with and without an intermediate thermal treatment step at 250 °C. Arsenic and gallium oxide removal was confirmed during this second deposition, leading to the inevitable conclusion that these oxides traversed at least 4 nm of film so as to react with the precursor and its surface reaction/decomposition byproducts. XPS measurements confirmed the relocation of both arsenic and gallium oxides from the interface to the bulk of the TiO2 film under normal processing conditions. These results explain the continuous native oxide removal observed for alkyl-amine precursor-based ALD processes on III-V surfaces and provide further insight into the mechanisms of film growth.

  20. Surface smoothing effect of an amorphous thin film deposited by atomic layer deposition on a surface with nano-sized roughness

    Directory of Open Access Journals (Sweden)

    W. S. Lau

    2014-02-01

    Full Text Available Previously, Lau (one of the authors pointed out that the deposition of an amorphous thin film by atomic layer deposition (ALD on a substrate with nano-sized roughness probably has a surface smoothing effect. In this letter, polycrystalline zinc oxide deposited by ALD onto a smooth substrate was used as a substrate with nano-sized roughness. Atomic force microscopy (AFM and cross-sectional transmission electron microscopy (XTEM were used to demonstrate that an amorphous aluminum oxide thin film deposited by ALD can reduce the surface roughness of a polycrystalline zinc oxide coated substrate.

  1. High Sensitivity Refractometer Based on TiO₂-Coated Adiabatic Tapered Optical Fiber via ALD Technology.

    Science.gov (United States)

    Zhu, Shan; Pang, Fufei; Huang, Sujuan; Zou, Fang; Guo, Qiang; Wen, Jianxiang; Wang, Tingyun

    2016-08-15

    Atomic layer deposition (ALD) technology is introduced to fabricate a high sensitivity refractometer based on an adiabatic tapered optical fiber. Different thicknesses of titanium dioxide (TiO₂) nanofilm were coated around the tapered fiber precisely and uniformly under different deposition cycles. Attributed to the higher refractive index of the TiO₂ nanofilm compared to that of silica, an asymmetric Fabry-Perot (F-P) resonator could be constructed along the fiber taper. The central wavelength of the F-P resonator could be controlled by adjusting the thickness of the TiO₂ nanofilm. Such a F-P resonator is sensitive to changes in the surrounding refractive index (SRI), which is utilized to realize a high sensitivity refractometer. The refractometer developed by depositing 50.9-nm-thickness TiO₂ on the tapered fiber shows SRI sensitivity as high as 7096 nm/RIU in the SRI range of 1.3373-1.3500. Due to TiO₂'s advantages of high refractive index, lack of toxicity, and good biocompatibility, this refractometer is expected to have wide applications in the biochemical sensing field.

  2. In-situ EELS and UPS measurements on HfO{sub 2} ALD layers

    Energy Technology Data Exchange (ETDEWEB)

    Michling, Marcel; Tallarida, Massimo; Kolanek, Krzysztof; Schmeisser, Dieter [Brandenburgische Technische Universitaet Cottbus, Angewandte Physik/Sensorik, Cottbus (Germany)

    2010-07-01

    In this contribution we report on our in-situ cycle-by-cycle (up to 10 cycles) investigations of the HfO{sub 2} ALD process using the methods of EELS and UPS. We used TDMA-Hf as a precursor and p-type Si wafer with natural oxide as the substrate. The EELS measurements were done with a primary energy of 52.5 eV and the UPS measurements with He I (21.218 eV). The change in the onset of the loss function is readily observed. Already after two cycles the value approach to the bulk value of HfO{sub 2}. Upon ALD growth there is a remarkable decrease in the intensity of states within the gap. They are rather smooth and saturate after 10 cycles. With UPS we follow the variation of the VB onset and changes in the secondary electron onset. We summarize our data in a band diagram not based on bulk values but on cycle dependent quantities. With these cycle-by-cycle experiments we study the initial growth of HfO{sub 2} especially in the very first cycles.

  3. Electrochemically Deposited Nickel Membranes; Process-Microstructure-Property Relationships

    DEFF Research Database (Denmark)

    Jensen, Jens Dahl; Pantleon, Karen; Somers, Marcel A.J.

    2003-01-01

    -type) or without (0-type) the use of the sulphur-containing additive sodium saccharin. Both types of Ni-foils appeared perfectly smooth when investigated with scanning electron microscopy (SEM), while atomic force microscopy (AFM) and transmission electron microscopy (TEM), revealed differences in the surface......-type foils during thin film tensile testing, due to microstructural defects caused by sodium saccharin during deposition. Tensile strengths in the order of 700-1000 MPa were observed - highest for the more ductile 0-type foils. A hardness in the order of 6 GPa (590 HV) was found by nanoindentation. Keywords...

  4. Electrochemically Deposited Nickel Membranes; Process-Microstructure-Property Relationships

    DEFF Research Database (Denmark)

    Jensen, Jens Dahl; Pantleon, Karen; Somers, Marcel A.J.

    2003-01-01

    -type) or without (0-type) the use of the sulphur-containing additive sodium saccharin. Both types of Ni-foils appeared perfectly smooth when investigated with scanning electron microscopy (SEM), while atomic force microscopy (AFM) and transmission electron microscopy (TEM), revealed differences in the surface......-type foils during thin film tensile testing, due to microstructural defects caused by sodium saccharin during deposition. Tensile strengths in the order of 700-1000 MPa were observed - highest for the more ductile 0-type foils. A hardness in the order of 6 GPa (590 HV) was found by nanoindentation. Keywords...

  5. Complex Materials by Atomic Layer Deposition.

    Science.gov (United States)

    Schwartzberg, Adam M; Olynick, Deirdre

    2015-10-14

    Complex materials are defined as nanostructured materials with combinations of structure and/or composition that lead to performance surpassing the sum of their individual components. There are many methods that can create complex materials; however, atomic layer deposition (ALD) is uniquely suited to control composition and structural parameters at the atomic level. The use of ALD for creating complex insulators, semiconductors, and conductors is discussed, along with its use in novel structural applications.

  6. Low temperature platinum atomic layer deposition on nylon-6 for highly conductive and catalytic fiber mats

    Energy Technology Data Exchange (ETDEWEB)

    Mundy, J. Zachary; Shafiefarhood, Arya; Li, Fanxing; Khan, Saad A.; Parsons, Gregory N., E-mail: gnp@ncsu.edu [Department of Chemical and Biomolecular Engineering, North Carolina State University, Engineering Building I, 911 Partners Way, Raleigh, North Carolina 27695-7905 (United States)

    2016-01-15

    Low temperature platinum atomic layer deposition (Pt-ALD) via (methylcyclopentadienyl)trimethyl platinum and ozone (O{sub 3}) is used to produce highly conductive nonwoven nylon-6 (polyamide-6, PA-6) fiber mats, having effective conductivities as high as ∼5500–6000 S/cm with only a 6% fractional increase in mass. The authors show that an alumina ALD nucleation layer deposited at high temperature is required to promote Pt film nucleation and growth on the polymeric substrate. Fractional mass gain scales linearly with Pt-ALD cycle number while effective conductivity exhibits a nonlinear trend with cycle number, corresponding to film coalescence. Field-emission scanning electron microscopy reveals island growth mode of the Pt film at low cycle number with a coalesced film observed after 200 cycles. The metallic coating also exhibits exceptional resistance to mechanical flexing, maintaining up to 93% of unstressed conductivity after bending around cylinders with radii as small as 0.3 cm. Catalytic activity of the as-deposited Pt film is demonstrated via carbon monoxide oxidation to carbon dioxide. This novel low temperature processing allows for the inclusion of highly conductive catalytic material on a number of temperature-sensitive substrates with minimal mass gain for use in such areas as smart textiles and flexible electronics.

  7. All-gas-phase synthesis of UiO-66 through modulated atomic layer deposition

    Science.gov (United States)

    Lausund, Kristian Blindheim; Nilsen, Ola

    2016-01-01

    Thin films of stable metal-organic frameworks (MOFs) such as UiO-66 have enormous application potential, for instance in microelectronics. However, all-gas-phase deposition techniques are currently not available for such MOFs. We here report on thin-film deposition of the thermally and chemically stable UiO-66 in an all-gas-phase process by the aid of atomic layer deposition (ALD). Sequential reactions of ZrCl4 and 1,4-benzenedicarboxylic acid produce amorphous organic–inorganic hybrid films that are subsequently crystallized to the UiO-66 structure by treatment in acetic acid vapour. We also introduce a new approach to control the stoichiometry between metal clusters and organic linkers by modulation of the ALD growth with additional acetic acid pulses. An all-gas-phase synthesis technique for UiO-66 could enable implementations in microelectronics that are not compatible with solvothermal synthesis. Since this technique is ALD-based, it could also give enhanced thickness control and the possibility to coat irregular substrates with high aspect ratios. PMID:27876797

  8. All-gas-phase synthesis of UiO-66 through modulated atomic layer deposition

    Science.gov (United States)

    Lausund, Kristian Blindheim; Nilsen, Ola

    2016-11-01

    Thin films of stable metal-organic frameworks (MOFs) such as UiO-66 have enormous application potential, for instance in microelectronics. However, all-gas-phase deposition techniques are currently not available for such MOFs. We here report on thin-film deposition of the thermally and chemically stable UiO-66 in an all-gas-phase process by the aid of atomic layer deposition (ALD). Sequential reactions of ZrCl4 and 1,4-benzenedicarboxylic acid produce amorphous organic-inorganic hybrid films that are subsequently crystallized to the UiO-66 structure by treatment in acetic acid vapour. We also introduce a new approach to control the stoichiometry between metal clusters and organic linkers by modulation of the ALD growth with additional acetic acid pulses. An all-gas-phase synthesis technique for UiO-66 could enable implementations in microelectronics that are not compatible with solvothermal synthesis. Since this technique is ALD-based, it could also give enhanced thickness control and the possibility to coat irregular substrates with high aspect ratios.

  9. Atomic-layer-deposition-assisted ZnO nanoparticles for oxide charge-trap memory thin-film transistors

    Science.gov (United States)

    Seo, Gi Ho; Yun, Da Jeong; Lee, Won Ho; Yoon, Sung Min

    2017-02-01

    ZnO nanoparticles (NPs) with monolayer structures were prepared by atomic layer deposition (ALD) to use for a charge-trap layer (CTL) for nonvolatile memory thin-film transistors (MTFTs). The optimum ALD temperature of the NP formation was demonstrated to be 160 °C. The size and areal density of the ZnO NPs was estimated to be approximately 33 nm and 4.8 × 109 cm-2, respectively, when the number of ALD cycles was controlled to be 20. The fabricated MTFTs using a ZnO-NP CTL exhibited typical memory window properties, which are generated by charge-trap/de-trap processes, in their transfer characteristics and the width of the memory window (MW) increased from 0.6 to 18.0 V when the number of ALD cycles increased from 5 to 30. The program characteristics of the MTFT were markedly enhanced by the post-annealing process performed at 180 °C in an oxygen ambient due to the improvements in the interface and bulk qualities of the ZnO NPs. The program/erase (P/E) speed was estimated to be 10 ms at P/E voltages of -14 and 17 V. The memory margin showed no degradation with the lapse in retention time for 2 × 104 s and after the repetitive P/E operations of 7 × 103 cycles.

  10. Final Report: Novel ALD-Coated Nanoparticle Anodes for Enhanced Performance Lithium-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Groner, Markus

    2009-04-16

    The Phase I effort is described in detail in the Phase I report given below. The key accomplishments of the Phase I project were (1) the demonstration of high stability LiCoO2 cathodes using ALD-coated LiCoO2 particles, as well as on ALD-coated LiCoO2 electrodes and (2) the demonstration of high stability of graphite anodes using ALD-coated graphite electrodes.

  11. New chemistry for the growth of first-row transition metal films by atomic layer deposition

    Science.gov (United States)

    Klesko, Joseph Peter

    Thin films containing first-row transition metals are widely used in microelectronic, photovoltaic, catalytic, and surface-coating applications. In particular, metallic films are essential for interconnects and seed, barrier, and capping layers in integrated circuitry. Traditional vapor deposition methods for film growth include PVD, CVD, or the use of plasma. However, these techniques lack the requisite precision for film growth at the nanoscale, and thus, are increasingly inadequate for many current and future applications. By contrast, ALD is the favored approach for depositing films with absolute surface conformality and thickness control on 3D architectures and in high aspect ratio features. However, the low-temperature chemical reduction of most first-row transition metal cations to their zero-valent state is very challenging due to their negative electrochemical potentials. A lack of strongly-reducing coreagents has rendered the thermal ALD of metallic films an intractable problem for many elements. Additionally, several established ALD processes for metal films are plagued by low growth rates, impurity incorporation, poor nucleation, high surface roughness, or the need for hazardous coreagents. Finally, stoichiometric control of ternary films grown by ALD is rare, but increasingly important, with emerging applications for metal borate films in catalysis and lithium ion batteries. The research herein is focused toward the development of new ALD processes for the broader application of metal, metal oxide, and metal borate thin films to future nanoscale technologies. These processes display self-limited growth and support the facile nucleation of smooth, continuous, high-purity films. Bis(trimethylsilyl) six-membered rings are employed as strongly-reducing organic coreagents for the ALD of titanium and antimony metal films. Additionally, new processes are developed for the growth of high-purity, low-resistivity cobalt and nickel metal films by exploiting the

  12. Integration of atomic layer deposited high-k dielectrics on GaSb via hydrogen plasma exposure

    Energy Technology Data Exchange (ETDEWEB)

    Ruppalt, Laura B., E-mail: laura.ruppalt@nrl.navy.mil; Cleveland, Erin R.; Champlain, James G.; Bennett, Brian R.; Prokes, Sharka M. [Electronics Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2014-12-15

    In this letter we report the efficacy of a hydrogen plasma pretreatment for integrating atomic layer deposited (ALD) high-k dielectric stacks with device-quality p-type GaSb(001) epitaxial layers. Molecular beam eptiaxy-grown GaSb surfaces were subjected to a 30 minute H{sub 2}/Ar plasma treatment and subsequently removed to air. High-k HfO{sub 2} and Al{sub 2}O{sub 3}/HfO{sub 2} bilayer insulating films were then deposited via ALD and samples were processed into standard metal-oxide-semiconductor (MOS) capacitors. The quality of the semiconductor/dielectric interface was probed by current-voltage and variable-frequency admittance measurements. Measurement results indicate that the H{sub 2}-plamsa pretreatment leads to a low density of interface states nearly independent of the deposited dielectric material, suggesting that pre-deposition H{sub 2}-plasma exposure, coupled with ALD of high-k dielectrics, may provide an effective means for achieving high-quality GaSb MOS structures for advanced Sb-based digital and analog electronics.

  13. Integration of atomic layer deposited high-k dielectrics on GaSb via hydrogen plasma exposure

    Directory of Open Access Journals (Sweden)

    Laura B. Ruppalt

    2014-12-01

    Full Text Available In this letter we report the efficacy of a hydrogen plasma pretreatment for integrating atomic layer deposited (ALD high-k dielectric stacks with device-quality p-type GaSb(001 epitaxial layers. Molecular beam eptiaxy-grown GaSb surfaces were subjected to a 30 minute H2/Ar plasma treatment and subsequently removed to air. High-k HfO2 and Al2O3/HfO2 bilayer insulating films were then deposited via ALD and samples were processed into standard metal-oxide-semiconductor (MOS capacitors. The quality of the semiconductor/dielectric interface was probed by current-voltage and variable-frequency admittance measurements. Measurement results indicate that the H2-plamsa pretreatment leads to a low density of interface states nearly independent of the deposited dielectric material, suggesting that pre-deposition H2-plasma exposure, coupled with ALD of high-k dielectrics, may provide an effective means for achieving high-quality GaSb MOS structures for advanced Sb-based digital and analog electronics.

  14. Atomic layer deposition precursor step repetition and surface plasma pretreatment influence on semiconductor–insulator–semiconductor heterojunction solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Talkenberg, Florian, E-mail: florian.talkenberg@ipht-jena.de; Illhardt, Stefan; Schmidl, Gabriele; Schleusener, Alexander; Sivakov, Vladimir [Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, D-07745 Jena (Germany); Radnóczi, György Zoltán; Pécz, Béla [Centre for Energy Research, Institute of Technical Physics and Materials Science, Konkoly-Thege Miklós u. 29-33, H-1121 Budapest (Hungary); Dikhanbayev, Kadyrjan; Mussabek, Gauhar [Department of Physics and Engineering, al-Farabi Kazakh National University, 71 al-Farabi Ave., 050040 Almaty (Kazakhstan); Gudovskikh, Alexander [Nanotechnology Research and Education Centre, St. Petersburg Academic University, Russian Academy of Sciences, Hlopina Str. 8/3, 194021 St. Petersburg (Russian Federation)

    2015-07-15

    Semiconductor–insulator–semiconductor heterojunction solar cells were prepared using atomic layer deposition (ALD) technique. The silicon surface was treated with oxygen and hydrogen plasma in different orders before dielectric layer deposition. A plasma-enhanced ALD process was applied to deposit dielectric Al{sub 2}O{sub 3} on the plasma pretreated n-type Si(100) substrate. Aluminum doped zinc oxide (Al:ZnO or AZO) was deposited by thermal ALD and serves as transparent conductive oxide. Based on transmission electron microscopy studies the presence of thin silicon oxide (SiO{sub x}) layer was detected at the Si/Al{sub 2}O{sub 3} interface. The SiO{sub x} formation depends on the initial growth behavior of Al{sub 2}O{sub 3} and has significant influence on solar cell parameters. The authors demonstrate that a hydrogen plasma pretreatment and a precursor dose step repetition of a single precursor improve the initial growth behavior of Al{sub 2}O{sub 3} and avoid the SiO{sub x} generation. Furthermore, it improves the solar cell performance, which indicates a change of the Si/Al{sub 2}O{sub 3} interface states.

  15. Characteristics of Single-Track and Multi-track Depositions of Stellite by Micro-plasma Transferred Arc Powder Deposition Process

    Science.gov (United States)

    Sawant, Mayur S.; Jain, N. K.

    2017-08-01

    This paper describes the characteristics study of single-track and multi-track deposition of Stellite 6 on AISI 4130 steel substrate by indigenously developed micro-plasma transferred arc powder deposition (μ-PTAPD) process. Deposition height and width, dilution and microstructure have been used to characterize the single-track depositions by studying effects of micro-plasma power, travel speed of worktable and powder mass flow rate on energy consumption per unit traverse length and power consumption per unit powder mass flow rate. Micro-plasma power was found to be the most influential parameter that affects energy and deposition material consumption. Consequently, its influence on micro-hardness and abrasion resistance of multi-track deposition was studied. Results showed that increase in micro-plasma power decreases micro-hardness and scratch hardness number and increases mean value of friction coefficient. Comparison of microstructure and chemical composition of single-track and multi-track depositions revealed that single-track has finer dendritic microstructure than the multi-track deposition. The black colored matrix and white colored dendrites present in the multi-track deposition have higher wt.% of cobalt and less wt.% of chromium than the single-track deposition. Comparison of µ-PTAPD process capabilities with the existing processes for Stellite deposition establishes that it is an energy-efficient, cost-effective and good quality deposition yielding process.

  16. Electrode surface engineering by atomic layer deposition: A promising pathway toward better energy storage

    KAUST Repository

    Ahmed, Bilal

    2016-04-29

    Research on electrochemical energy storage devices including Li ion batteries (LIBs), Na ion batteries (NIBs) and supercapacitors (SCs) has accelerated in recent years, in part because developments in nanomaterials are making it possible to achieve high capacities and energy and power densities. These developments can extend battery life in portable devices, and open new markets such as electric vehicles and large-scale grid energy storage. It is well known that surface reactions largely determine the performance and stability of electrochemical energy storage devices. Despite showing impressive capacities and high energy and power densities, many of the new nanostructured electrode materials suffer from limited lifetime due to severe electrode interaction with electrolytes or due to large volume changes. Hence control of the surface of the electrode material is essential for both increasing capacity and improving cyclic stability of the energy storage devices.Atomic layer deposition (ALD) which has become a pervasive synthesis method in the microelectronics industry, has recently emerged as a promising process for electrochemical energy storage. ALD boasts excellent conformality, atomic scale thickness control, and uniformity over large areas. Since ALD is based on self-limiting surface reactions, complex shapes and nanostructures can be coated with excellent uniformity, and most processes can be done below 200. °C. In this article, we review recent studies on the use of ALD coatings to improve the performance of electrochemical energy storage devices, with particular emphasis on the studies that have provided mechanistic insight into the role of ALD in improving device performance. © 2016 Elsevier Ltd.

  17. Study of the deposition process of vinpocetine on the surface of porous silicon

    Science.gov (United States)

    Lenshin, A. S.; Polkovnikova, Yu. A.; Seredin, P. V.

    Currently the most prospective way in pharmacotherapy is the obtaining of nanoparticles involving pharmaceutical substances. Application of porous inorganic materials on the basis of silicon is among the main features in solving of this problem. The present work is concerned with the problem of the deposition of pharmaceutical drug with nootropic activity - vinpocetine - into porous silicon. Silicon nanoparticles were obtained by electrochemical anodic etching of Si plates. The process of vinpocetine deposition was studied in dependence of the deposition time. As a result of the investigations it was found that infrared transmission spectra of porous silicon with the deposited vinpocetine revealed the absorption bands characteristic of vinpocetine substance.

  18. Performance characterization of Ni60-WC coating on steel processed with supersonic laser deposition

    Directory of Open Access Journals (Sweden)

    Fang Luo

    2015-03-01

    Full Text Available Ni60-WC particles are used to improve the wear resistance of hard-facing steel due to their high hardness. An emerging technology that combines laser with cold spraying to deposit the hard-facing coatings is known as supersonic laser deposition. In this study, Ni60-WC is deposited on low-carbon steel using SLD. The microstructure and performance of the coatings are investigated through SEM, optical microscopy, EDS, XRD, microhardness and pin-on-disc wear tests. The experimental results of the coating processed with the optimal parameters are compared to those of the coating deposited using laser cladding.

  19. Effect of process parameters on induction plasma reactive deposition of tungsten carbide from tungsten metal powder

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Tungsten carbide deposit was made directly from tungsten metal powder through the reaction with methane in radio frequency induction plasma. Effect of major process parameters on the induction plasma reactive deposition of tungsten carbide was studied by optical microscopy, scanning electron microscopy, X-ray diffraction analysis, water displacement method, and microhardness test. The results show that methane flow rate, powder feed rate, particle size, reaction chamber pressure and deposition distance have significant influences on the phase composition, density, and microhardness of the deposit. Extra carbon is necessary to ensure the complete conversion of tungsten metal into the carbide.

  20. Effect of surface pretreatment on interfacial chemical bonding states of atomic layer deposited ZrO{sub 2} on AlGaN

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Gang; Arulkumaran, Subramaniam; Ng, Geok Ing; Li, Yang; Ang, Kian Siong [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Wang, Hong, E-mail: ewanghong@ntu.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore and CINTRA CNRS/NTU/Thales, UMI 3288, 50 Nanyang Drive, Singapore 637553 (Singapore); Ng, Serene Lay Geok; Ji, Rong [Data Storage Institute, Agency for Science Technology and Research (A-STAR), 5 Engineering Drive 1, Singapore 117608 (Singapore); Liu, Zhi Hong [Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, Singapore 138602 (Singapore)

    2015-09-15

    Atomic layer deposition (ALD) of ZrO{sub 2} on native oxide covered (untreated) and buffered oxide etchant (BOE) treated AlGaN surface was analyzed by utilizing x-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy. Evidenced by Ga–O and Al–O chemical bonds by XPS, parasitic oxidation during deposition is largely enhanced on BOE treated AlGaN surface. Due to the high reactivity of Al atoms, more prominent oxidation of Al atoms is observed, which leads to thicker interfacial layer formed on BOE treated surface. The results suggest that native oxide on AlGaN surface may serve as a protecting layer to inhibit the surface from further parasitic oxidation during ALD. The findings provide important process guidelines for the use of ALD ZrO{sub 2} and its pre-ALD surface treatments for high-k AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors and other related device applications.

  1. Photocatalytic activity and photocorrosion of atomic layer deposited ZnO ultrathin films for the degradation of methylene blue.

    Science.gov (United States)

    Cao, Yan-Qiang; Chen, Jun; Zhou, Hang; Zhu, Lin; Li, Xin; Cao, Zheng-Yi; Wu, Di; Li, Ai-Dong

    2015-01-16

    ZnO ultrathin films with varied thicknesses of 7-70 nm were prepared at 200 °C on Si and fused quartz substrates by atomic layer deposition (ALD). The impact of film thickness and annealing temperature on the crystallinity, morphology, optical bandgap, and photocatalytic properties of ZnO in the degradation of methylene blue (MB) dye under UV light irradiation (λ = 365 nm) has been investigated deeply. The as-deposited 28 nm thick ZnO ultrathin film exhibits highest photocatalytic activity, ascribed to the smallest band gap of 3.21 eV and proper thickness. The photocorrosion effect of ALD ZnO ultrathin films during photocatalytic process is observed. The presence of MB significantly accelerates the dissolution of ZnO ultrathin films. The possible photoetching mechanism of ZnO in MB solution is proposed.

  2. Work function tuning of plasma-enhanced atomic layer deposited WC{sub x}N{sub y} electrodes for metal/oxide/semiconductor devices

    Energy Technology Data Exchange (ETDEWEB)

    Zonensain, Oren; Fadida, Sivan; Eizenberg, Moshe [Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Fisher, Ilanit; Gao, Juwen; Chattopadhyay, Kaushik; Harm, Greg; Mountsier, Tom; Danek, Michal [Lam Research Corporation, 4000 N. First Street, San Jose, California 95134 (United States)

    2015-02-23

    One of the main challenges facing the integration of metals as gate electrodes in advanced MOS devices is control over the Fermi level position at the metal/dielectric interface. In this study, we demonstrate the ability to tune the effective work function (EWF) of W-based electrodes by process modifications of the atomic layer deposited (ALD) films. Tungsten carbo-nitrides (WC{sub x}N{sub y}) films were deposited via plasma-enhanced and/or thermal ALD processes using organometallic precursors. The process modifications enabled us to control the stoichiometry of the WC{sub x}N{sub y} films. Deposition in hydrogen plasma (without nitrogen based reactant) resulted in a stoichiometry of WC{sub 0.4} with primarily W-C chemical bonding, as determined by x-ray photoelectron spectroscopy. These films yielded a relatively low EWF of 4.2 ± 0.1 eV. The introduction of nitrogen based reactant to the plasma or the thermal ALD deposition resulted in a stoichiometry of WC{sub 0.1}N{sub 0.6–0.8} with predominantly W-N chemical bonding. These films produced a high EWF of 4.7 ± 0.1 eV.

  3. Gravimetric measurements with use of a cantilever for controlling of electrochemical deposition processes

    Science.gov (United States)

    Prokaryn, Piotr; Janus, Pawel; Zajac, Jerzy; Sierakowski, Andrzej; Domanski, Krzysztof; Grabiec, Piotr

    2016-11-01

    In this paper we describe the method for monitoring the progress of electrochemical deposition process. The procedure allows to control the deposition of metals as well as conductive polymers on metallic seed layer. The method is particularly useful to very thin layers (1-10 nm) of deposited medium which mechanical or optical methods are troublesome for. In this method deposit is grown on the target and on the test silicon micro-cantilever with a metal pad. Galvanic deposition on the cantilever causes the change of its mass and consequently the change of its resonance frequency. Changes of the frequency is measured with laser vibro-meter then the layer thicknesses can be estimated basing on the cantilever calibration curve. Applying this method for controlling of gold deposition on platinum seed layer, for improving the properties of the biochemical sensors, is described in this paper.

  4. Atomic layer deposition assisted pattern transfer technology for ultra-thin block copolymer films

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wenhui; Luo, Jun; Meng, Lingkuan; Li, Junjie; Xiang, Jinjuan; Li, Junfeng; Wang, Wenwu; Chen, Dapeng; Ye, Tianchun; Zhao, Chao

    2016-08-31

    As an emerging developing technique for next-generation lithography, directed self-assembly (DSA) of block copolymer (BCP) has attracted numerous attention and has been a potential alternative to supplement the intrinsic limitations of conventional photolithography. In this work, the self-assembling properties of a lamellar diblock copolymer poly(styrene-b-methylmethacrylate) (PS-b-PMMA, 22k-b-22k, L{sub 0} = 25 nm) on Si substrate and an atomic layer deposition (ALD)-assisted pattern transfer technology for the application of DSA beyond 16/14 nm complementary metal oxide semiconductor (CMOS) technology nodes, were investigated. Firstly, two key processing parameters of DSA, i.e. annealing temperatures and durations of BCP films, were optimized to achieve low defect density and high productivity. After phase separation of BCP films, self-assembling patterns of low defect density should be transferred to the substrate. However, due to the nano-scale thickness and the weak resistance of BCP films to dry etching, it is nearly impossible to transfer the BCP patterns directly to the substrate. Therefore, an ALD-based technology was explored in this work, in which deposited Al{sub 2}O{sub 3} selectively reacts with PMMA blocks thus hardening the PMMA patterns. After removing PS blocks by plasma etching, hardened PMMA patterns were left and transferred to underneath SiO{sub 2} hard mask layer. Using this patterned hard mask, nanowire array of 25 nm pitch were realized on Si substrate. From this work, a high-throughput DSA baseline flow and related ALD-assisted pattern transfer technique were developed and proved to have good capability with the mainstream CMOS technology. - Highlights: • Optimization on self-assembly process for high productivity and low defectivity • Enhancement of etching ratio and resistance by atomic layer deposition (ALD) • A hard mask was used for pattern quality improvement and contamination control.

  5. Electroless deposition process for zirconium and zirconium alloys

    Science.gov (United States)

    Donaghy, Robert E.; Sherman, Anna H.

    1981-01-01

    A method is disclosed for preventing stress corrosion cracking or metal embrittlement of a zirconium or zirconium alloy container that is to be coated on the inside surface with a layer of a metal such as copper, a copper alloy, nickel, or iron and used for holding nuclear fuel material as a nuclear fuel element. The zirconium material is etched in an etchant solution, desmutted mechanically or ultrasonically, oxidized to form an oxide coating on the zirconium, cleaned in an aqueous alkaline cleaning solution, activated for electroless deposition of a metal layer and contacted with an electroless metal plating solution. This method provides a boundary layer of zirconium oxide between the zirconium container and the metal layer.

  6. Low-temperature atomic layer deposition of copper(II) oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Iivonen, Tomi, E-mail: tomi.iivonen@helsinki.fi; Hämäläinen, Jani; Mattinen, Miika; Popov, Georgi; Leskelä, Markku [Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki (Finland); Marchand, Benoît; Mizohata, Kenichiro [Division of Materials Physics, Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 Helsinki (Finland); Kim, Jiyeon; Fischer, Roland A. [Chair of Inorganic Chemistry II, Ruhr-University Bochum, Universitätsstrasse 150, 44780 Bochum (Germany)

    2016-01-15

    Copper(II) oxide thin films were grown by atomic layer deposition (ALD) using bis-(dimethylamino-2-propoxide)copper [Cu(dmap){sub 2}] and ozone in a temperature window of 80–140 °C. A thorough characterization of the films was performed using x-ray diffraction, x-ray reflectivity, UV‐Vis spectrophotometry, atomic force microscopy, field emission scanning electron microscopy, x-ray photoelectron spectroscopy, and time-of-flight elastic recoil detection analysis techniques. The process was found to produce polycrystalline copper(II) oxide films with a growth rate of 0.2–0.3 Å per cycle. Impurity content in the films was relatively small for a low temperature ALD process.

  7. Atmospheric pressure plasma enhanced spatial ALD of silver

    Energy Technology Data Exchange (ETDEWEB)

    Bruele, Fieke J. van den, E-mail: Fieke.vandenBruele@tno.nl; Smets, Mireille; Illiberi, Andrea; Poodt, Paul [Holst Centre/TNO, High Tech Campus 31, 5656 AE Eindhoven (Netherlands); Creyghton, Yves [TNO, High Tech Campus 21, 5656 AE Eindhoven (Netherlands); Buskens, Pascal [TNO, Rondom 1, 5612 AP Eindhoven, The Netherlands and DWI Leibniz-Institut für Interaktive Materialien, Aachen (Germany); Roozeboom, Fred [TNO, High Tech Campus 21, 5656 AE Eindhoven, The Netherlands and Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands)

    2015-01-15

    The authors have investigated the growth of thin silver films using a unique combination of atmospheric process elements: spatial atomic layer deposition and an atmospheric pressure surface dielectric barrier discharge plasma source. Silver films were grown on top of Si substrates with good purity as revealed by resistivity values as low as 18 μΩ cm and C- and F-levels below detection limits of energy dispersive x-ray analysis. The growth of the silver films starts through the nucleation of islands that subsequently coalesce. The authors show that the surface island morphology is dependent on surface diffusion, which can be controlled by temperature within the deposition temperature range of 100–120 °C.

  8. The Research and Development of the External Magnetic Field Acting on Electro-Deposition Process

    Directory of Open Access Journals (Sweden)

    Wu Menghua

    2016-01-01

    Full Text Available The research and development status of the electro-deposition technology under the action of external magnetic field are introduced. The basic characteristics and applied manners of external magnetic field in electro-deposition process are summarized. The acting principle of external magnetic field, the effects of magnetic hydrodynamics (MHD caused by the Lorentz force, and the acting of magnetic force on the metal ions and particles are described. The main actions of external magnetic field include MHD effect, magnetizing force, affecting the physical and chemical properties of the bath, affecting the disperse ability and coverage capacity of bath, affecting the mass transfer process of electro-deposition, affecting the chemical reaction process and current distribution of electrode surface. Some examples of electro-depositing single metal coatings, alloy coatings and composite coatings under action of magnetic field are explained. During the electro-depositing process, the external magnetic field has different degrees of impact on solution properties, mass transfer, charge transfer, content of composited nanoparticles, crystal growth and crystal orientation etc. The specific impact of magnetic field during the electro-depositing is also classified and summarized. The problems that existed in electro-deposition process while applying magnetic field and the next development trend were summarized.

  9. Atomistic study of deposition process of Al thin film on Cu substrate

    Energy Technology Data Exchange (ETDEWEB)

    Cao Yongzhi, E-mail: yzcaohit@gmail.com [Center for Precision Engineering, Harbin Institute of Technology, Harbin (China); Zhang Junjie; Sun Tao; Yan Yongda; Yu Fuli [Center for Precision Engineering, Harbin Institute of Technology, Harbin (China)

    2010-08-01

    In this paper we report molecular dynamics based atomistic simulations of deposition process of Al atoms onto Cu substrate and following nanoindentation process on that nanostructured material. Effects of incident energy on the morphology of deposited thin film and mechanical property of this nanostructured material are emphasized. The results reveal that the morphology of growing film is layer-by-layer-like at incident energy of 0.1-10 eV. The epitaxy mode of film growth is observed at incident energy below 1 eV, but film-mixing mode commences when incident energy increase to 10 eV accompanying with increased disorder of film structure, which improves quality of deposited thin film. Following indentation studies indicate deposited thin films pose lower stiffness than single crystal Al due to considerable amount of defects existed in them, but Cu substrate is strengthened by the interface generated from lattice mismatch between deposited Al thin film and Cu substrate.

  10. An Introduction to Atomic Layer Deposition with Thermal Applications

    Science.gov (United States)

    Dwivedi, Vivek H.

    2015-01-01

    Atomic Layer Deposition (ALD) is a cost effective nano-manufacturing technique that allows for the conformal coating of substrates with atomic control in a benign temperature and pressure environment. Through the introduction of paired precursor gases thin films can be deposited on a myriad of substrates ranging from glass, polymers, aerogels, and metals to high aspect ratio geometries. This talk will focus on the utilization of ALD for engineering applications.

  11. High energy high rate pulsed power processing of materials by powder consolidation and by railgun deposition

    Science.gov (United States)

    Persad, C.; Marcus, H. L.; Weldon, W. F.

    1987-03-01

    This exploratory research program was initiated to investigate the potential of using pulse power sources for powder consolidation, deposition and other High Energy High Rate Processing. The characteristics of the High Energy High Rate (1MJ/s) powder consolidation using megampere current pulses from a Homopolar Generator, have been defined. Molybdenum Alloy TZM, A Nickel based metallic glass, Copper graphite composites, and P/M Aluminum Alloy X7091 have been investigated. The powder consolidation process produced high densification rates. Density values of 80% to 99% could be obtained with sub second high temperature exposure. Specific energy input and applied pressure were controlling process parameters. Time Temperature Transformation (TTT) concepts underpin a fundamental understanding of pulsed power processing. Deposition experiments were conducted using an exploding foil device (EFD) providing an armature feed to railgun mounted in a vacuum chamber. The material to be deposited - in plasma, gas, liquid or solid state - was accelerated electromagnetically in the railgun and deposited on a substrate.

  12. Si surface passivation by Al2O3 thin films deposited using a low thermal budget atomic layer deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Seguini, G.; Cianci, E.; Wiemer, C.; Perego, M. [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate Brianza MB (Italy); Saynova, D.; Van Roosmalen, J.A.M. [ECN Solar Energy, Westerduinweg 3, NL-1755 ZG Petten (Netherlands)

    2013-04-05

    High-quality surface passivation of crystalline Si is achieved using 10 nm thick Al2O3 films fabricated by thermal atomic layer deposition at 100C. After a 5 min post deposition annealing at 200C, the effective carrier lifetime is 1 ms, indicating a functional level of surface passivation. The interplay between the chemical and the field effect passivation is investigated monitoring the density of interface traps and the amount of fixed charges with conductance-voltage and capacitance-voltage techniques. The physical mechanisms underlying the surface passivation are described. The combination of low processing temperatures, thin layers, and good passivation properties facilitate a technology for low-temperature solar cells.

  13. The influence of tertiary butyl hydrazine as a co-reactant on the atomic layer deposition of silver

    Science.gov (United States)

    Golrokhi, Zahra; Marshall, Paul A.; Romani, Simon; Rushworth, Simon; Chalker, Paul R.; Potter, Richard J.

    2017-03-01

    Ultra-thin conformal silver films are the focus of development for applications such as anti-microbial surfaces, optical components and electronic devices. In this study, metallic silver films have been deposited using direct liquid injection thermal atomic layer deposition (ALD) using (hfac)Ag(1,5-COD) ((hexafluoroacetylacetonato)silver(I)(1,5-cyclooctadiene)) as the metal source and tertiary butyl hydrazine (TBH) as a co-reactant. The process provides a 23 °C wide 'self-limiting' ALD temperature window between 105 and 128 °C, which is significantly wider than is achievable using alcohol as a co-reactant. A mass deposition rate of ∼20 ng/cm2/cycle (∼0.18 Å/cycle) is observed under self-limiting growth conditions. The resulting films are crystalline metallic silver with a near planar film-like morphology which are electrically conductive. By extending the temperature range of the ALD window by the use of TBH as a co-reactant, it is envisaged that the process will be exploitable in a range of new low temperature applications.

  14. Influence of process parameters on the preparation of pharmaceutical films by electrostatic powder deposition.

    Science.gov (United States)

    Prasad, Leena Kumari; LaFountaine, Justin S; Keen, Justin M; Williams, Robert O; McGinity, James W

    2016-12-30

    Electrostatic powder deposition (ESPD) has been developed as a solvent-free method to prepare pharmaceutical films. The aim of this work was to investigate the influence of process parameters during (1) electrostatic powder deposition, (2) curing, and (3) removal of the film from the substrate on the properties of the film. Polyethylene oxide (PEO) was used as the model polymer and stainless steel 316 as the substrate. Deposition efficiency (i.e. deposited weight) was measured with varying charging voltage, gun tip to substrate distance, and environmental humidity. Scanning electron microscopy was utilized to assess film formation, and adhesive and mechanical strength of films were measured with varying cure temperature and time. Adhesive strength was measured for films prepared on substrates of varying surface roughness. When deposition was performed at low humidity conditions, 25%RH, process parameters did not significantly affect deposition behavior. At 40%RH, increasing deposition efficiency with decreasing gun tip to substrate distance and increasing voltage (up to 60kV) was observed. Complete film formation was seen by 30min at 80°C, compared to lower curing temperatures and times. All films were readily removed from the substrates. The results show the ESPD process can be modified to produce films with good mechanical properties (e.g. tensile strength>0.06MPa), suggesting it is a promising dry powder process for preparing pharmaceutical films.

  15. Evaluation of Alternative Atomistic Models for the Incipient Growth of ZnO by Atomic Layer Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Manh-Hung; Tian, Liang; Chaker, Ahmad; Skopin, Evgenii; Cantelli, Valentina; Ouled, Toufik; Boichot, Raphaël; Crisci, Alexandre; Lay, Sabine; Richard, Marie-Ingrid; Thomas, Olivier; Deschanvres, Jean-Luc; Renevier, Hubert; Fong, Dillon; Ciatto, Gianluca

    2017-03-20

    ZnO thin films are interesting for applications in several technological fields, including optoelectronics and renewable energies. Nanodevice applications require controlled synthesis of ZnO structures at nanometer scale, which can be achieved via atomic layer deposition (ALD). However, the mechanisms governing the initial stages of ALD had not been addressed until very recently. Investigations into the initial nucleation and growth as well as the atomic structure of the heterointerface are crucial to optimize the ALD process and understand the structure-property relationships for ZnO. We have used a complementary suite of in situ synchrotron x-ray techniques to investigate both the structural and chemical evolution during ZnO growth by ALD on two different substrates, i.e., SiO2 and Al2O3, which led us to formulate an atomistic model of the incipient growth of ZnO. The model relies on the formation of nanoscale islands of different size and aspect ratio and consequent disorder induced in the Zn neighbors' distribution. However, endorsement of our model requires testing and discussion of possible alternative models which could account for the experimental results. In this work, we review, test, and rule out several alternative models; the results confirm our view of the atomistic mechanisms at play, which influence the overall microstructure and resulting properties of the final thin film.

  16. Evaluation of Alternative Atomistic Models for the Incipient Growth of ZnO by Atomic Layer Deposition

    Science.gov (United States)

    Chu, Manh-Hung; Tian, Liang; Chaker, Ahmad; Skopin, Evgenii; Cantelli, Valentina; Ouled, Toufik; Boichot, Raphaël; Crisci, Alexandre; Lay, Sabine; Richard, Marie-Ingrid; Thomas, Olivier; Deschanvres, Jean-Luc; Renevier, Hubert; Fong, Dillon; Ciatto, Gianluca

    2017-03-01

    ZnO thin films are interesting for applications in several technological fields, including optoelectronics and renewable energies. Nanodevice applications require controlled synthesis of ZnO structures at nanometer scale, which can be achieved via atomic layer deposition (ALD). However, the mechanisms governing the initial stages of ALD had not been addressed until very recently. Investigations into the initial nucleation and growth as well as the atomic structure of the heterointerface are crucial to optimize the ALD process and understand the structure-property relationships for ZnO. We have used a complementary suite of in situ synchrotron x-ray techniques to investigate both the structural and chemical evolution during ZnO growth by ALD on two different substrates, i.e., SiO2 and Al2O3, which led us to formulate an atomistic model of the incipient growth of ZnO. The model relies on the formation of nanoscale islands of different size and aspect ratio and consequent disorder induced in the Zn neighbors' distribution. However, endorsement of our model requires testing and discussion of possible alternative models which could account for the experimental results. In this work, we review, test, and rule out several alternative models; the results confirm our view of the atomistic mechanisms at play, which influence the overall microstructure and resulting properties of the final thin film.

  17. Method for Aluminum Oxide Thin Films Prepared through Low Temperature Atomic Layer Deposition for Encapsulating Organic Electroluminescent Devices

    Directory of Open Access Journals (Sweden)

    Hui-Ying Li

    2015-02-01

    Full Text Available Preparation of dense alumina (Al2O3 thin film through atomic layer deposition (ALD provides a pathway to achieve the encapsulation of organic light emitting devices (OLED. Unlike traditional ALD which is usually executed at higher reaction n temperatures that may affect the performance of OLED, this application discusses the development on preparation of ALD thin film at a low temperature. One concern of ALD is the suppressing effect of ambient temperature on uniformity of thin film. To mitigate this issue, the pumping time in each reaction cycle was increased during the preparation process, which removed reaction byproducts and inhibited the formation of vacancies. As a result, the obtained thin film had both high uniformity and density properties, which provided an excellent encapsulation performance. The results from microstructure morphology analysis, water vapor transmission rate, and lifetime test showed that the difference in uniformity between thin films prepared at low temperatures, with increased pumping time, and high temperatures was small and there was no obvious influence of increased pumping time on light emitting performance. Meanwhile, the permeability for water vapor of the thin film prepared at a low temperature was found to reach as low as 1.5 × 10−4 g/(m2·day under ambient conditions of 25 °C and 60% relative humidity, indicating a potential extension in the lifetime for the OLED.

  18. Effect of Energy Input on the Characteristic of AISI H13 and D2 Tool Steels Deposited by a Directed Energy Deposition Process

    Science.gov (United States)

    Park, Jun Seok; Park, Joo Hyun; Lee, Min-Gyu; Sung, Ji Hyun; Cha, Kyoung Je; Kim, Da Hye

    2016-05-01

    Among the many additive manufacturing technologies, the directed energy deposition (DED) process has attracted significant attention because of the application of metal products. Metal deposited by the DED process has different properties than wrought metal because of the rapid solidification rate, the high thermal gradient between the deposited metal and substrate, etc. Additionally, many operating parameters, such as laser power, beam diameter, traverse speed, and powder mass flow rate, must be considered since the characteristics of the deposited metal are affected by the operating parameters. In the present study, the effect of energy input on the characteristics of H13 and D2 steels deposited by a direct metal tooling process based on the DED process was investigated. In particular, we report that the hardness of the deposited H13 and D2 steels decreased with increasing energy input, which we discuss by considering microstructural observations and thermodynamics.

  19. Corrosion protection of silver-based telescope mirrors using evaporated anti-oxidation overlayers and aluminum oxide films by atomic layer deposition

    Science.gov (United States)

    Fryauf, David M.; Phillips, Andrew C.; Kobayashi, Nobuhiko P.

    2016-09-01

    An urgent demand remains in astronomy for high-reflectivity silver mirrors that can withstand years of exposure in observatory environments. The University of California Observatories Astronomical Coatings Lab has undertaken development of protected silver coatings suitable for telescope mirrors that maintain high reflectivity at wavelengths from 340 nm through the mid-infrared spectrum. We present results on superior protective layers of transparent dielectrics produced by evaporation and atomic layer deposition. Several novel coating recipes have been developed with ion-assisted electron beam deposition (IAEBD) of various fluorides, oxides, and nitrides in combination with conformal layers of aluminum oxide (AlOx) deposited by ALD using trimethylaluminum as a metal precursor and water vapor as a reactant. Extending on our previous results demonstrating the superior durability of ALD-based AlOx top barrier layers over conventionally-deposited AlOx, this work investigates the effects on mirror barrier durability comparing different anti-oxidation materials on Ag with an identical AlOx top barrier layer deposited by ALD. Samples of coating recipes with different anti-oxidation layers undergo aggressive environmental testing, including high temperature/high humidity (HTHH), in which samples are exposed to an environment of 80% humidity at 80°C for ten days in a simple test set-up. While most samples show fairly successful endurance after HTHH testing, visible results suggest that MgAl2O4, Al2O3, and AlN anti-oxidation layers offer enhanced robust protection against chemical corrosion and moisture in an accelerated aging environment, which is attributed to superior adhesion and intermolecular bonding between the Al-based anti-oxidation layers and the AlOx top barrier layer. Mirror samples are further characterized by reflectivity/absorption before and after deposition of oxide coatings. We also show that the performance of the ALD-AlOx barrier layer depends in part

  20. Investigation of Tin (Sn) Film Using an Aerosol Jet Additive Manufacturing Deposition Process

    Science.gov (United States)

    Fortier, Aleksandra; Liu, Yue; Ghamarian, Iman; Collins, Peter C.; Chason, Eric

    2017-08-01

    The quality of a Sn film deposited by the aerosol process is compared against the quality of Sn films deposited with traditional electroplating. Using the aerosol additive deposition technique, a Sn film was deposited on a brass substrate and exposed to room (25°C) temperature environments for 30 days, followed by a laser photosintering process. The film characteristics and content, formation of intermetallic compounds, residual stress distribution, grain texture, and the tendency of the film to grow Sn whiskers were analyzed. The preliminary results show a successful deposition of Sn film with an aerosol jet process and tensile residual stresses, whereas it was compressive in nature for electroplated Sn film. X-ray diffraction results also show the absence of intermetallic compound (IMC) formation in the aerosol jet-deposited film, while electroplated Sn film has a significant presence of IMC. The aerosol jet-deposited Sn film has the potential to resist nucleation of Sn whiskers under the operating conditions used in this study.

  1. A sub-atmospheric chemical vapor deposition process for deposition of oxide liner in high aspect ratio through silicon vias.

    Science.gov (United States)

    Lisker, Marco; Marschmeyer, Steffen; Kaynak, Mehmet; Tekin, Ibrahim

    2011-09-01

    The formation of a Through Silicon Via (TSV) includes a deep Si trench etching and the formation of an insulating layer along the high-aspect-ratio trench and the filling of a conductive material into the via hole. The isolation of the filling conductor from the silicon substrate becomes more important for higher frequencies due to the high coupling of the signal to the silicon. The importance of the oxide thickness on the via wall isolation can be verified using electromagnetic field simulators. To satisfy the needs on the Silicon dioxide deposition, a sub-atmospheric chemical vapor deposition (SA-CVD) process has been developed to deposit an isolation oxide to the walls of deep silicon trenches. The technique provides excellent step coverage of the 100 microm depth silicon trenches with the high aspect ratio of 20 and more. The developed technique allows covering the deep silicon trenches by oxide and makes the high isolation of TSVs from silicon substrate feasible which is the key factor for the performance of TSVs for mm-wave 3D packaging.

  2. The erosion performance of cold spray deposited metal matrix composite coatings with subsequent friction stir processing

    Science.gov (United States)

    Peat, Tom; Galloway, Alexander; Toumpis, Athanasios; McNutt, Philip; Iqbal, Naveed

    2017-02-01

    This study forms an initial investigation into the development of SprayStir, an innovative processing technique for generating erosion resistant surface layers on a chosen substrate material. Tungsten carbide - cobalt chromium, chromium carbide - nickel chromium and aluminium oxide coatings were successfully cold spray deposited on AA5083 grade aluminium. In order to improve the deposition efficiency of the cold spray process, coatings were co-deposited with powdered AA5083 using a twin powder feed system that resulted in thick (>300 μm) composite coatings. The deposited coatings were subsequently friction stir processed to embed the particles in the substrate in order to generate a metal matrix composite (MMC) surface layer. The primary aim of this investigation was to examine the erosion performance of the SprayStirred surfaces and demonstrate the benefits of this novel process as a surface engineering technique. Volumetric analysis of the SprayStirred surfaces highlighted a drop of approx. 40% in the level of material loss when compared with the cold spray deposited coating prior to friction stir processing. Micro-hardness testing revealed that in the case of WC-CoCr reinforced coating, the hardness of the SprayStirred material exhibits an increase of approx. 540% over the unaltered substrate and 120% over the as-deposited composite coating. Microstructural examination demonstrated that the increase in the hardness of the MMC aligns with the improved dispersion of reinforcing particles throughout the aluminium matrix.

  3. Preparation and Characterization of TaN ALD Precursors

    Institute of Scientific and Technical Information of China (English)

    Delong Zhang; Tracy Yund; Cynthia A.Hoover

    2004-01-01

    High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET > PDMAT > TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.

  4. La sélection d'Aldébaran

    Directory of Open Access Journals (Sweden)

    2012-07-01

    Full Text Available http://aldebaran.revues.org Aldébaran est une revue électronique en libre accès qui propose une sélection de ressources documentaires en sciences humaines à travers des notices de sites et des conseils de recherche. Les notices présentées dans ce numéro ont été rédigées par Françoise Acquier (CRESSON, Véronique Ginouvès (MMSH et Samuel Mazet (CRESSON. AIVP - Association Internationale Villes et Ports. Le réseau mondial des villes portuaires http://aldebaran.revues.org/6617 Fondé en 1988, l...

  5. La sélection d'Aldébaran

    Directory of Open Access Journals (Sweden)

    2012-12-01

    Full Text Available Aldébaran est une revue électronique en libre accès qui propose une sélection de ressources documentaires en sciences humaines à travers des notices de sites et des conseils de recherche. Les notices présentées dans ce numéro ont été rédigées par Julien Gillet (Cléo, Véronique Ginouvès (MMSH USR3125 et François Siino (IREMAM. BCAI - Bulletin critique des Annales islamologiques http://aldebaran.revues.org/6075 Le Bulletin critique des Annales islamologiques vise à rendre compte de toute pu...

  6. La sélection d'Aldébaran

    Directory of Open Access Journals (Sweden)

    Françoise Acquier

    2014-12-01

    Full Text Available Aldébaran est une revue électronique en libre accès qui propose une sélection de ressources documentaires en sciences humaines à travers des notices de sites et des conseils de recherche. Les notices présentées dans ce numéro ont été rédigées par Françoise Acquier (CRESSON, Grenoble et Véronique Ginouvès (MMSH USR3125. Conversion of Islamic and Christian dates http://aldebaran.revues.org/7169 J. Thomann, de l'Institut d'études asiatiques et orientales (Institute of Asian and Oriental Studie...

  7. La sélection d'Aldébaran

    Directory of Open Access Journals (Sweden)

    2012-07-01

    Full Text Available http://aldebaran.revues.org Aldébaran est une revue électronique en libre accès qui propose une sélection des ressources documentaires en sciences humaines à travers des notices de sites et des conseils de recherche. Les notices présentées dans ce numéro ont été rédigées par Julien Gillet (Ifpo, Jean-Christophe Peyssard (Revues.org et Anaïs Salomon (Bibliothèque des études islamiques de l'Université McGill Islamic Heritage Project - Harvard University Library http://aldebaran.revues.org/65...

  8. La sélection d'Aldébaran

    Directory of Open Access Journals (Sweden)

    2012-07-01

    Full Text Available Aldébaran est une revue électronique en libre accès qui propose une sélection de ressources documentaires en sciences humaines à travers des notices de sites et des conseils de recherche. Les notices présentées dans ce numéro ont été rédigées par Anaïs Salamon (Bibliothèque des études islamiques de l’Université McGill. AAU – Association of Arab Universities http://aldebaran.revues.org/6888 Fondée en 1969 et affiliée à la Ligue arabe, l’Association des Universités Arabes (AAU compte aujourd’...

  9. La sélection d'Aldébaran

    Directory of Open Access Journals (Sweden)

    Françoise Acquier

    2013-12-01

    Full Text Available Aldébaran est une revue électronique en libre accès qui propose une sélection de ressources documentaires en sciences humaines à travers des notices de sites et des conseils de recherche. Les notices présentées dans ce numéro ont été rédigées par Véronique Ginouvès (MMSH USR3125 et Françoise Acquier (CRESSON. Arab Cinema Directory [http://aldebaran.revues.org/6945] Le site  « Arab Cinema Directory » rassemble des informations sur plus de 6 500 films arabes depuis les années 1930 jusqu'à auj...

  10. La sélection d'Aldébaran

    Directory of Open Access Journals (Sweden)

    Françoise Acquier

    2014-09-01

    Full Text Available Aldébaran est une revue électronique en libre accès qui propose une sélection de ressources documentaires en sciences humaines à travers des notices de sites et des conseils de recherche. Les notices présentées dans ce numéro ont été rédigées par Françoise Acquier (CRESSON, Grenoble, Fabrice Melka (IMAF, Julien Gillet (Cléo et Véronique Ginouvès (MMSH USR3125. Afriterra. The Cartographic Free Library http://aldebaran.revues.org/6775 La fondation Afriterra, à but non lucratif, est une bibl...

  11. La sélection d'Aldébaran

    Directory of Open Access Journals (Sweden)

    Véronique Ginouvès

    2013-10-01

    Full Text Available Aldébaran est une revue électronique en libre accès qui propose une sélection de ressources documentaires en sciences humaines à travers des notices de sites et des conseils de recherche. Les notices présentées dans ce numéro ont été rédigées par Véronique Ginouvès (MMSH USR3125, Annick Richard (MMSH USR3125 et Anaïs Salamon (Bibliothèque Mac Gill. AREU - Afghanistan Research and Evaluation Unit http://aldebaran.revues.org/7031 L'Afghanistan Research and Evaluation Unit (AREU propose une ...

  12. Al2 O3 Underlayer Prepared by Atomic Layer Deposition for Efficient Perovskite Solar Cells.

    Science.gov (United States)

    Zhang, Jinbao; Hultqvist, Adam; Zhang, Tian; Jiang, Liangcong; Ruan, Changqing; Yang, Li; Cheng, Yibing; Edoff, Marika; Johansson, Erik M J

    2017-08-31

    Perovskite solar cells, as an emergent technology for solar energy conversion, have attracted much attention in the solar cell community by demonstrating impressive enhancement in power conversion efficiencies. However, the high temperature and manually processed TiO2 underlayer prepared by spray pyrolysis significantly limit the large-scale application and device reproducibility of perovskite solar cells. In this study, lowtemperature atomic layer deposition (ALD) is used to prepare a compact Al2 O3 underlayer for perovskite solar cells. The thickness of the Al2 O3 layer can be controlled well by adjusting the deposition cycles during the ALD process. An optimal Al2 O3 layer effectively blocks electron recombination at the perovskite/fluorine-doped tin oxide interface and sufficiently transports electrons through tunneling. Perovskite solar cells fabricated with an Al2 O3 layer demonstrated a highest efficiency of 16.2 % for the sample with 50 ALD cycles (ca. 5 nm), which is a significant improvement over underlayer-free PSCs, which have a maximum efficiency of 11.0 %. Detailed characterization confirms that the thickness of the Al2 O3 underlayer significantly influences the charge transfer resistance and electron recombination processes in the devices. Furthermore, this work shows the feasibility of using a high band-gap semiconductor such as Al2 O3 as the underlayer in perovskite solar cells and opens up pathways to use ALD Al2 O3 underlayers for flexible solar cells. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Breakthrough to Non-Vacuum Deposition of Single-Crystal, Ultra-Thin, Homogeneous Nanoparticle Layers: A Better Alternative to Chemical Bath Deposition and Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Yu-Kuang Liao

    2017-04-01

    Full Text Available Most thin-film techniques require a multiple vacuum process, and cannot produce high-coverage continuous thin films with the thickness of a few nanometers on rough surfaces. We present a new ”paradigm shift” non-vacuum process to deposit high-quality, ultra-thin, single-crystal layers of coalesced sulfide nanoparticles (NPs with controllable thickness down to a few nanometers, based on thermal decomposition. This provides high-coverage, homogeneous thickness, and large-area deposition over a rough surface, with little material loss or liquid chemical waste, and deposition rates of 10 nm/min. This technique can potentially replace conventional thin-film deposition methods, such as atomic layer deposition (ALD and chemical bath deposition (CBD as used by the Cu(In,GaSe2 (CIGS thin-film solar cell industry for decades. We demonstrate 32% improvement of CIGS thin-film solar cell efficiency in comparison to reference devices prepared by conventional CBD deposition method by depositing the ZnS NPs buffer layer using the new process. The new ZnS NPs layer allows reduction of an intrinsic ZnO layer, which can lead to severe shunt leakage in case of a CBD buffer layer. This leads to a 65% relative efficiency increase.

  14. Deposition and post-processing techniques for transparent conductive films

    Energy Technology Data Exchange (ETDEWEB)

    Christoforo, Mark Greyson; Mehra, Saahil; Salleo, Alberto; Peumans, Peter

    2017-07-04

    In one embodiment, a method is provided for fabrication of a semitransparent conductive mesh. A first solution having conductive nanowires suspended therein and a second solution having nanoparticles suspended therein are sprayed toward a substrate, the spraying forming a mist. The mist is processed, while on the substrate, to provide a semitransparent conductive material in the form of a mesh having the conductive nanowires and nanoparticles. The nanoparticles are configured and arranged to direct light passing through the mesh. Connections between the nanowires provide conductivity through the mesh.

  15. Rare earth-doped alumina thin films deposited by liquid source CVD processes

    Energy Technology Data Exchange (ETDEWEB)

    Deschanvres, J.L.; Meffre, W.; Joubert, J.C.; Senateur, J.P. [Ecole Nat. Superieure de Phys. de Grenoble, St. Martin d`Heres (France). Lab. des Materiaux et du Genie Phys.; Robaut, F. [Consortium des Moyens Technologiques Communs, Institut National Polytechnique de Grenoble, BP 75, 38402 St Martin d`Heres (France); Broquin, J.E.; Rimet, R. [Laboratoire d`Electromagnetisme, Microondes et Optoelectronique, CNRS-Ecole Nationale Superieure d`Electronique et Radioelectricite de Grenoble, BP 257, 38016 Grenoble, Cedex (France)

    1998-07-24

    Two types of liquid-source CVD processes are proposed for the growth of rare earth-doped alumina thin films suitable as amplifying media for integrated optic applications. Amorphous, transparent, pure and erbium- or neodymium-doped alumina films were deposited between 573 and 833 K by atmospheric pressure aerosol CVD. The rare earth doping concentration increases by decreasing the deposition temperature. The refractive index of the alumina films increases as a function of the deposition temperature from 1.53 at 573 K to 1.61 at 813 K. Neodymium-doped films were also obtained at low pressure by liquid source injection CVD. (orig.) 7 refs.

  16. Al2O3 on Black Phosphorus by Atomic Layer Deposition: An in Situ Interface Study.

    Science.gov (United States)

    Zhu, Hui; McDonnell, Stephen; Qin, Xiaoye; Azcatl, Angelica; Cheng, Lanxia; Addou, Rafik; Kim, Jiyoung; Ye, Peide D; Wallace, Robert M

    2015-06-17

    In situ "half cycle" atomic layer deposition (ALD) of Al2O3 was carried out on black phosphorus ("black-P") surfaces with modified phosphorus oxide concentrations. X-ray photoelectron spectroscopy is employed to investigate the interfacial chemistry and the nucleation of the Al2O3 on black-P surfaces. This work suggests that exposing a sample that is initially free of phosphorus oxide to the ALD precursors does not result in detectable oxidation. However, when the phosphorus oxide is formed on the surface prior to deposition, the black-P can react with both the surface adventitious oxygen contamination and the H2O precursor at a deposition temperature of 200 °C. As a result, the concentration of the phosphorus oxide increases after both annealing and the atomic layer deposition process. The nucleation rate of Al2O3 on black-P is correlated with the amount of oxygen on samples prior to the deposition. The growth of Al2O3 follows a "substrate inhibited growth" behavior where an incubation period is required. Ex situ atomic force microscopy is also used to investigate the deposited Al2O3 morphologies on black-P where the Al2O3 tends to form islands on the exfoliated black-P samples. Therefore, surface functionalization may be needed to get a conformal coverage of Al2O3 on the phosphorus oxide free samples.

  17. Highly conductive and flexible nylon-6 nonwoven fiber mats formed using tungsten atomic layer deposition.

    Science.gov (United States)

    Kalanyan, Berç; Oldham, Christopher J; Sweet, William J; Parsons, Gregory N

    2013-06-12

    Low-temperature vapor-phase tungsten atomic layer deposition (ALD) using WF6 and dilute silane (SiH4, 2% in Ar) can yield highly conductive coatings on nylon-6 microfiber mats, producing flexible and supple nonwovens with conductivity of ∼1000 S/cm. We find that an alumina nucleation layer, reactant exposure, and deposition temperature all influence the rate of W mass uptake on 3D fibers, and film growth rate is calibrated using high surface area anodic aluminum oxide. Transmission electron microscopy (TEM) reveals highly conformal tungsten coatings on nylon fibers with complex "winged" cross-section. Using reactant gas "hold" sequences during the ALD process, we conclude that reactant species can transport readily to reactive sites throughout the fiber mat, consistent with conformal uniform coverage observed by TEM. The conductivity of 1000 S/cm for the W-coated nylon is much larger than found in other conductive nonwovens. We also find that the nylon mats maintain 90% of their conductivity after being flexed around cylinders with radii as small as 0.3 cm. Metal ALD coatings on nonwovens make possible the solvent-free functionalization of textiles for electronic applications.

  18. Advancement in additive manufacturing & numerical modelling considerations of direct energy deposition process

    OpenAIRE

    Quanren Zeng; Zhenhai Xu; Yankang Tian; Yi Qin

    2016-01-01

    The development speed and application range of the additive manufacturing (AM) processes, such as selective laser melting (SLM), laser metal deposition (LMD) or laser-engineering net shaping (LENS), are ever-increasing in modern advanced manufacturing field for rapid manufacturing, tooling repair or surface enhancement of the critical metal components. LMD is based on a kind of directed energy deposition (DED) technology which ejects a strand of metal powders into a moving molten pool caused ...

  19. The Research and Development of the External Magnetic Field Acting on Electro-Deposition Process

    OpenAIRE

    Wu Menghua; Jia Weiping

    2016-01-01

    The research and development status of the electro-deposition technology under the action of external magnetic field are introduced. The basic characteristics and applied manners of external magnetic field in electro-deposition process are summarized. The acting principle of external magnetic field, the effects of magnetic hydrodynamics (MHD) caused by the Lorentz force, and the acting of magnetic force on the metal ions and particles are described. The main actions of external magnetic field...

  20. Influence of process parameters on atomic layer deposition of ZrO{sub 2} thin films from CpZr(NMe{sub 2}){sub 3} and H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Aarik, Lauri, E-mail: lauri.aarik@ut.ee [University of Tartu, Institute of Physics, Ravila 14C, 50411 Tartu (Estonia); Alles, Harry; Aidla, Aleks; Kahro, Tauno [University of Tartu, Institute of Physics, Ravila 14C, 50411 Tartu (Estonia); Kukli, Kaupo [University of Tartu, Institute of Physics, Ravila 14C, 50411 Tartu (Estonia); University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); Niinistö, Jaakko [University of Helsinki, Department of Chemistry, P.O. Box 55, FI-00014 Helsinki (Finland); Mändar, Hugo; Tamm, Aile; Rammula, Raul [University of Tartu, Institute of Physics, Ravila 14C, 50411 Tartu (Estonia); Sammelselg, Väino [University of Tartu, Institute of Physics, Ravila 14C, 50411 Tartu (Estonia); University of Tartu, Institute of Chemistry, Ravila 14A, 50411 Tartu (Estonia); Aarik, Jaan [University of Tartu, Institute of Physics, Ravila 14C, 50411 Tartu (Estonia)

    2014-08-28

    Atomic layer deposition of ZrO{sub 2} films from tris(dimethylamino)cyclopentadienylzirconium CpZr(NMe{sub 2}){sub 3} and H{sub 2}O, was investigated using real-time characterization of the growth process and post-growth measurements of the films. Self-limited nature of the deposition process was observed at substrate temperatures ranging from 120 to 350 °C. In this temperature range growth rate of 0.08–0.1 nm per cycle was obtained on silicon substrates. The films deposited on silicon substrates at 200 °C and higher temperatures contained tetragonal and monoclinic phases of ZrO{sub 2}. The phase composition of the films depended on the deposition temperature as well as on the film thickness. The concentration of carbon residues decreased with increasing deposition temperature and did not exceed 0.9 at.% in the films deposited at 250 °C and higher temperatures. The refractive indices and densities of films grown from CpZr(NMe{sub 2}){sub 3} and H{sub 2}O at 250–350 °C ranged from 2.15 to 2.20 (at a wavelength of 633 nm) and 5.6 to 6.0 g/cm{sup 3}, respectively, being close to the highest values obtained for films deposited from ZrCl{sub 4} and H{sub 2}O. The former process ensured, however, more uniform nucleation of ZrO{sub 2} on graphene than the latter process did. - Highlights: • Thin films were grown from CpZr(NMe{sub 2}){sub 3} and H{sub 2}O on Si substrates by ALD. • The growth of ZrO{sub 2} was obtained at temperatures 120–350 °C. • Growth rates up to 0.1 nm per cycle were observed. • Films with refractive indices up to 2.2 at 633 nm were obtained.

  1. Electronic properties of atomic layer deposition films, anatase and rutile TiO2 studied by resonant photoemission spectroscopy

    Science.gov (United States)

    Das, C.; Richter, M.; Tallarida, M.; Schmeisser, D.

    2016-07-01

    The TiO2 films are prepared by atomic layer deposition (ALD) method using titanium isopropoxide precursors at 250 °C and analyzed using resonant photoemission spectroscopy (resPES). We report on the Ti2p and O1s core levels, on the valence band (VB) spectra and x-ray absorption spectroscopy (XAS) data, and on the resonant photoelectron spectroscopy (resPES) profiles at the O1s and the Ti3p absorption edges. We determine the elemental abundance, the position of the VB maxima, the partial density of states (PDOS) in the VB and in the conduction band (CB) and collect these data in a band scheme. In addition, we analyze the band-gap states as well as the intrinsic states due to polarons and charge-transfer excitations. These states are found to cause multiple Auger decay processes upon resonant excitation. We identify several of these processes and determine their relative contribution to the Auger signal quantitatively. As our resPES data allow a quantitative analysis of these defect states, we determine the relative abundance of the PDOS in the VB and in CB and also the charge neutrality level. The anatase and rutile polymorphs of TiO2 are analyzed in the same way as the TiO2 ALD layer. The electronic properties of the TiO2 ALD layer are compared with the anatase and rutile polymorphs of TiO2. In our comparative study, we find that ALD has its own characteristic electronic structure that is distinct from that of anatase and rutile. However, many details of the electronic structure are comparable and we benefit from our spectroscopic data and our careful analysis to find these differences. These can be attributed to a stronger hybridization of the O2p and Ti3d4s states for the ALD films when compared to the anatase and rutile polymorphs.

  2. Comparison of deposited surface area of airborne ultrafine particles generated from two welding processes.

    Science.gov (United States)

    Gomes, J F; Albuquerque, P C; Miranda, Rosa M; Santos, Telmo G; Vieira, M T

    2012-09-01

    This article describes work performed on the assessment of the levels of airborne ultrafine particles emitted in two welding processes metal-active gas (MAG) of carbon steel and friction-stir welding (FSW) of aluminium in terms of deposited area in alveolar tract of the lung using a nanoparticle surface area monitor analyser. The obtained results showed the dependence from process parameters on emitted ultrafine particles and clearly demonstrated the presence of ultrafine particles, when compared with background levels. The obtained results showed that the process that results on the lower levels of alveolar-deposited surface area is FSW, unlike MAG. Nevertheless, all the tested processes resulted in important doses of ultrafine particles that are to be deposited in the human lung of exposed workers.

  3. Effect of Source, Surfactant, and Deposition Process on Electronic Properties of Nanotube Arrays

    Directory of Open Access Journals (Sweden)

    Dheeraj Jain

    2011-01-01

    Full Text Available The electronic properties of arrays of carbon nanotubes from several different sources differing in the manufacturing process used with a variety of average properties such as length, diameter, and chirality are studied. We used several common surfactants to disperse each of these nanotubes and then deposited them on Si wafers from their aqueous solutions using dielectrophoresis. Transport measurements were performed to compare and determine the effect of different surfactants, deposition processes, and synthesis processes on nanotubes synthesized using CVD, CoMoCAT, laser ablation, and HiPCO.

  4. Atomic layer deposition of copper and copper silver films using an electrochemical process

    Energy Technology Data Exchange (ETDEWEB)

    Fang, J.S., E-mail: jsfang@nfu.edu.tw [Department of Materials Science and Engineering, National Formosa University, Huwei 63201, Taiwan (China); Liu, Y.S. [Department of Materials Science and Engineering, National Formosa University, Huwei 63201, Taiwan (China); Chin, T.S. [Department of Materials Science and Engineering, Feng Chia University, Taichung 40724, Taiwan (China)

    2015-04-01

    This paper describes the formation and properties of Cu and Cu(Ag) films on a Ru/Si substrate using electrochemical atomic layer deposition. The process was performed layer-by-layer using underpotential deposition (UPD) and surface-limited redox reactions. The first Cu atomic layer was deposited on the Ru/Si substrate via UPD. Using UPD, atomic layered of Pb, which acts as a sacrificial layer, was applied on the Cu layer. Then, a Cu{sup 2+} solution was flushed into the cell at an open-circuit potential, and the Pb layer was exchanged for Cu via redox replacements. The above sequences were repeated 500 times to form a Cu film. The Cu(Ag) alloy films were formed using Cu–UPD and Ag–UPD in predetermined sequences. The lowest electrical resistivity achieved was 3.6 and 2.2 μΩ cm for the Cu film and Cu(Ag) film, respectively, after annealing at 400 °C. Due to the self-limiting reactions, the process has the ability to deposit atomic layers to meet the requirement of Cu interconnects. - Highlights: • Layer-by-layer growth of Cu and Cu(Ag) films are prepared using electrochemical atomic layer deposition. • Cu coverage is from 0.33 to 0.51 ML for each deposition cycle in different NaCl concentrations. • The process can be applied in Cu interconnections.

  5. Comparison of B{sub 2}O{sub 3} and BN deposited by atomic layer deposition for forming ultrashallow dopant regions by solid state diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Consiglio, Steven, E-mail: steve.consiglio@us.tel.com; Clark, Robert D.; O' Meara, David; Wajda, Cory S.; Tapily, Kandabara; Leusink, Gert J. [TEL Technology Center, America, LLC, 255 Fuller Rd., Albany, New York 12203 (United States)

    2016-01-15

    In this study, the authors investigated atomic layer deposition (ALD) of B{sub 2}O{sub 3} and BN for conformal, ultrashallow B doping applications and compared the effect of dopant-containing overlayers on sheet resistance (R{sub s}) and B profiles for both types of films subjected to a drive-in thermal anneal. For the deposition of B{sub 2}O{sub 3}, tris(dimethylamido)borane and O{sub 3} were used as coreactants and for the deposition of BN, BCl{sub 3} and NH{sub 3} were used as coreactants. Due to the extreme air instability of B{sub 2}O{sub 3} films, physical analysis was performed on B{sub 2}O{sub 3} films, which were capped in-situ with ∼30 Å ALD grown Al{sub 2}O{sub 3} layers. For the BN films, in-situ ALD grown Si{sub 3}N{sub 4} capping layers (∼30 Å) were used for comparison. From spectroscopic ellipsometry, a thickness decrease was observed after 1000 °C, 30 s anneal for the B{sub 2}O{sub 3} containing stack with 60 ALD cycles of B{sub 2}O{sub 3}, whereas the BN containing stacks showed negligible thickness decrease after the annealing step, regardless of the number of BN cycles tested. The postanneal reduction in film thickness as well as decrease in R{sub s} for the B{sub 2}O{sub 3} containing stack suggests that the solid state diffusion dopant mechanism is effective, whereas for the BN containing stacks this phenomenon seems to be suppressed. Further clarification of the effectiveness of the B{sub 2}O{sub 3} containing layer compared to the film stacks with BN was evidenced in backside secondary ion mass spectrometry profiling of B atoms. Thus, B{sub 2}O{sub 3} formed by an ALD process and subsequently capped in-situ followed by a drive-in anneal offers promise as a dopant source for ultrashallow doping, whereas the same method using BN seems ineffective. An integrated approach for B{sub 2}O{sub 3} deposition and annealing on a clustered tool also demonstrated controllable R{sub s} reduction without the use of a capping layer.

  6. Highly Anti-UV Properties of Silk Fiber with Uniform and Conformal Nanoscale TiO2 Coatings via Atomic Layer Deposition.

    Science.gov (United States)

    Xiao, Xingfang; Liu, Xin; Chen, Fengxiang; Fang, Dong; Zhang, Chunhua; Xia, Liangjun; Xu, Weilin

    2015-09-30

    In this study, silk fiber was successfully modified via the application of a nanoscale titania coating using atomic layer deposition (ALD), with titanium tetraisopropoxide (TIP) and water as precursors at 100 °C. Scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscope, and field emission scanning electron microscope results demonstrated that uniform and conformal titania coatings were deposited onto the silk fiber. The thermal and mechanical properties of the TiO2 silk fiber were then investigated. The results showed that the thermal stability and mechanical properties of this material were superior to those of the uncoated substance. Furthermore, the titania ALD process provided the silk fiber with excellent protection against UV radiation. Specifically, the TiO2-coated silk fibers exhibited significant increases in UV absorbance, considerably less yellowing, and greatly enhanced mechanical properties compared with the uncoated silk fiber after UV exposure.

  7. Empirical-Statistical Study on the Relationship between Deposition Parameters, Process Variables, Deposition Rate and Mechanical Properties of a-C:H:W Coatings

    Directory of Open Access Journals (Sweden)

    Harald Hetzner

    2014-12-01

    Full Text Available Tungsten-modified hydrogenated amorphous carbon coatings (a-C:H:W were deposited on high speed steel by reactive magnetron sputtering of a tungsten carbide target in an argon-ethine atmosphere. The deposition parameters, sputtering power, bias voltage, argon and ethine flow rate, were varied according to a central composite design comprising 25 different parameter combinations. For comparison, a tungsten carbide coating was deposited, as well. During coating deposition, the process variables, total pressure, sputtering voltage and bias current, were measured as process characteristics. The thickness of the deposited coatings was determined using the crater grinding method, and the deposition rate was calculated. Young’s modulus E and indentation hardness HIT were characterized by means of nanoindentation. With E = 80

  8. Apparatus and process for atomic or molecular layer deposition onto particles during pneumatic transport

    NARCIS (Netherlands)

    Van Ommen, J.R.

    2010-01-01

    The invention provides a process for depositing a coating onto particles being pneumatically transported in a tube. The process comprising the steps of providing a tube having an inlet opening and an outlet opening; feeding a carrier gas entraining particles into the tube at or near the inlet openin

  9. Crystal Structure of Mycobacterium tuberculosis H37Rv AldR (Rv2779c), a Regulator of the ald Gene: DNA BINDING AND IDENTIFICATION OF SMALL MOLECULE INHIBITORS.

    Science.gov (United States)

    Dey, Abhishek; Shree, Sonal; Pandey, Sarvesh Kumar; Tripathi, Rama Pati; Ramachandran, Ravishankar

    2016-06-03

    Here we report the crystal structure of M. tuberculosis AldR (Rv2779c) showing that the N-terminal DNA-binding domains are swapped, forming a dimer, and four dimers are assembled into an octamer through crystal symmetry. The C-terminal domain is involved in oligomeric interactions that stabilize the oligomer, and it contains the effector-binding sites. The latter sites are 30-60% larger compared with homologs like MtbFFRP (Rv3291c) and can consequently accommodate larger molecules. MtbAldR binds to the region upstream to the ald gene that is highly up-regulated in nutrient-starved tuberculosis models and codes for l-alanine dehydrogenase (MtbAld; Rv2780). Further, the MtbAldR-DNA complex is inhibited upon binding of Ala, Tyr, Trp and Asp to the protein. Studies involving a ligand-binding site G131T mutant show that the mutant forms a DNA complex that cannot be inhibited by adding the amino acids. Comparative studies suggest that binding of the amino acids changes the relative spatial disposition of the DNA-binding domains and thereby disrupt the protein-DNA complex. Finally, we identified small molecules, including a tetrahydroquinoline carbonitrile derivative (S010-0261), that inhibit the MtbAldR-DNA complex. The latter molecules represent the very first inhibitors of a feast/famine regulatory protein from any source and set the stage for exploring MtbAldR as a potential anti-tuberculosis target.

  10. Investigation of defects in ultra-thin Al{sub 2}O{sub 3} films deposited on pure copper by the atomic layer deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Chang, M.L.; Wang, L.C. [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Lin, H.C., E-mail: hclinntu@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Chen, M.J., E-mail: mjchen@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Lin, K.M. [Department of Materials Science and Engineering, Feng Chia University, No. 100, Wenhwa Road, Seatwen, Taichung 40724, Taiwan (China)

    2015-12-30

    Graphical abstract: Some residual OH ligands originating from incomplete reaction between TMA and surface species of OH* during ALD process induce the defects in deposited Al{sub 2}O{sub 3} films. Three possible types of defects are suggested. The analytic results indicate the defects are Type-I and/or Type-II but do not directly expose the substrate, like pinholes (Type-III). - Highlights: • Oxidation trials were conducted to investigate the defects in ultra-thin Al{sub 2}O{sub 3} films deposited ALD technique on pure copper. • The residual OH ligands in the deposited Al{sub 2}O{sub 3} films induce looser micro-structure which has worse oxidation resistance. • Superficial contamination particles on substrate surface are confirmed to be one of nucleation sites of the defects. - Abstract: Al{sub 2}O{sub 3} films with various thicknesses were deposited by the atomic layer deposition (ALD) technique on pure copper at temperatures of 100–200 °C. Oxidation trials were conducted in air at 200 °C to investigate the defects in these films. The analytic results show that the defects have a looser micro-structure compared to their surroundings, but do not directly expose the substrate, like pinholes. The film's crystallinity, mechanical properties and oxidation resistance could also be affected by these defects. Superficial contamination particles on the substrate surface are confirmed to be nucleation sites of the defects. A model for the mechanism of defect formation is proposed in this study.

  11. Process sedimentology of submarine fan deposits - new perspectives

    Science.gov (United States)

    Postma, George

    2017-04-01

    To link submarine fan process sedimentology with sand distribution, sand body architecture, texture and fabric, the field geologist studies sedimentary facies, facies associations (fan elements) and stratigraphy. Facies analysis resides on factual knowledge of modern fan morphodynamics and physical modelling of en-masse sediment transport. Where do we stand after 55 years of submarine research, i.e. the date when the first submarine fan model was launched by Arnold Bouma in 1962? Since that date students of submarine fans have worked on a number of important, recurring questions concerned with facies analysis of submarine successions in outcrop and core: 1. What type of sediment transport produced the beds? 2. What facies can be related to initial flow conditions? 3. What is the significance of grain size jumps and bounding surface hierarchy in beds consisting of crude and spaced stratification (traction carpets)? Do these point to multi flow events or to flow pulsations by one and the same event? 4. What facies associations relate to the basic elements of submarine fans? 5. What are the autogenic and allogenic signatures in submarine fans? Particularly in the last decade, the enormous technical advancement helped to obtain high-quality data from observations of density flows in modern canyons, deep basins and deep-water delta slopes (refs 1,2,3). In combination with both physical (refs 4,5) and numerical modelling (ref 6) these studies broke new ground into our understanding of density flow processes in various submarine environments and have led to new concepts of submarine fan building by super- and subcritical high-density flow (ref 7). Do these new concepts provide better answers to our recurrent questions related to the morphodynamics of submarine fans and prediction of sand body architecture? In discussing this open question, I shall 1. apply the new concepts to a modern and ancient example of a channel-lobe-transition-zone (ref 8); 2. raise the problem of

  12. Tri-gate InGaAs-OI junctionless FETs with PE-ALD Al2O3 gate dielectric and H2/Ar anneal

    Science.gov (United States)

    Djara, Vladimir; Czornomaz, Lukas; Deshpande, Veeresh; Daix, Nicolas; Uccelli, Emanuele; Caimi, Daniele; Sousa, Marilyne; Fompeyrine, Jean

    2016-01-01

    We present a tri-gate In0.53Ga0.47As-on-insulator (InGaAs-OI) junctionless field-effect transistor (JLFET) architecture. The fabricated devices feature a 20-nm-thick n-In0.53Ga0.47As channel doped to 1018/cm3 obtained by metal organic chemical vapor phase deposition and direct wafer bonding along with a 3.5-nm-thick Al2O3 gate dielectric deposited by plasma-enhanced atomic layer deposition (PE-ALD). The PE-ALD Al2O3 presents a bandgap of 7.0 eV, a k-value of 8.1 and a breakdown field of 8-10.5 MV/cm. A post-fabrication H2/Ar anneal applied to the PE-ALD Al2O3/In0.53Ga0.47As-OI gate stack yielded a low density of interface traps (Dit) of 7 × 1011/cm2 eV at Ec - E = -0.1 eV along with lower border trap density values than recently reported PE-ALD bi-layer Al2O3/HfO2 and thermal ALD HfO2 gate stacks deposited on In0.53Ga0.47As. The H2/Ar anneal also improved the subthreshold performance of the tri-gate InGaAs-OI JLFETs. After H2/Ar anneal, the long-channel (10 μm) device featured a threshold voltage (VT) of 0.25 V, a subthreshold swing (SS) of 88 mV/dec and a drain-induced barrier lowering (DIBL) of 65 mV/V, while the short-channel (160 nm) device exhibited a VT of 0.1 V, a SS of 127 mV/dec and a DIBL of 218 mV/V. Overall, the tri-gate InGaAs-OI JLFETs showed the best compromise in terms of VT, SS and DIBL compared to the other III-V JLFET architectures reported to date. However, a 15× increase in access resistance was observed after H2/Ar anneal, significantly degrading the maximum drain current of the tri-gate InGaAs-OI JLFETs.

  13. In situ gas phase measurements during metal alkylamide atomic layer deposition.

    Science.gov (United States)

    Maslar, J E; Kimes, W A; Sperling, B A

    2011-09-01

    Metal alkylamide compounds, such as tetrakis(ethylmethylamido) hafnium (TEMAH), represent a technologically important class of metalorganic precursors for the deposition of metal oxides and metal nitrides via atomic layer deposition (ALD) or chemical vapor deposition. The development of in situ diagnostics for processes involving these compounds could be beneficial in, e.g., developing deposition recipes and validating equipment-scale simulations. This report describes the performance of the combination of two techniques for the simultaneous, rapid measurement of the three major gas phase species during hafnium oxide thermal ALD using TEMAH and water: TEMAH, water, and methylethyl amine (MEA), the only major reaction by-product. For measurement of TEMAH and MEA, direct absorption methods based on a broadband infrared source with different mid-IR bandpass filters and utilizing amplitude modulation and synchronous detection were developed. For the measurement of water, wavelength modulation spectroscopy utilizing a near-IR distributed feedback diode laser was used. Despite the relatively simple reactor geometry employed here (a flow tube), differences were easily observed in the time-dependent species distributions in 300 mL/min of a helium carrier gas and in 1000 mL/min of a nitrogen carrier gas. The degree of TEMAH entrainment was lower in 300 mL/min of helium compared to that in 1000 mL/min of nitrogen. The capability to obtain detailed time-dependent species concentrations during ALD could potentially allow for the selection of carrier gas composition and flow rates that would minimize parasitic wall reactions. However, when nitrogen was employed at the higher flow rates, various flow effects were observed that, if detrimental to a deposition process, would effectively limit the upper range of useful flow rates.

  14. Modelling and optimization of film thickness variation for plasma enhanced chemical vapour deposition processes

    Science.gov (United States)

    Waddell, Ewan; Gibson, Des; Lin, Li; Fu, Xiuhua

    2011-09-01

    This paper describes a method for modelling film thickness variation across the deposition area within plasma enhanced chemical vapour deposition (PECVD) processes. The model enables identification and optimization of film thickness uniformity sensitivities to electrode configuration, temperature, deposition system design and gas flow distribution. PECVD deposition utilizes a co-planar 300mm diameter electrodes with separate RF power matching to each electrode. The system has capability to adjust electrode separation and electrode temperature as parameters to optimize uniformity. Vacuum is achieved using dry pumping with real time control of butterfly valve position for active pressure control. Comparison between theory and experiment is provided for PECVD of diamond-like-carbon (DLC) deposition onto flat and curved substrate geometries. The process utilizes butane reactive feedstock with an argon carrier gas. Radiofrequency plasma is used. Deposited film thickness sensitivities to electrode geometry, plasma power density, pressure and gas flow distribution are demonstrated. Use of modelling to optimise film thickness uniformity is demonstrated. Results show DLC uniformity of 0.30% over a 200 mm flat zone diameter within overall electrode diameter of 300mm. Thickness uniformity of 0.75% is demonstrated over a 200mm diameter for a non-conformal substrate geometry. Use of the modelling method for PECVD using metal-organic chemical vapour deposition (MOCVD) feedstock is demonstrated, specifically for deposition of silica films using metal-organic tetraethoxy-silane. Excellent agreement between experimental and theory is demonstrated for conformal and non-conformal geometries. The model is used to explore scalability of PECVD processes and trade-off against film thickness uniformity. Application to MEMS, optical coatings and thin film photovoltaics is discussed.

  15. Continuous production of nanostructured particles using spatial atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ommen, J. Ruud van, E-mail: j.r.vanommen@tudelft.nl; Kooijman, Dirkjan; Niet, Mark de; Talebi, Mojgan; Goulas, Aristeidis [Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft (Netherlands)

    2015-03-15

    In this paper, the authors demonstrate a novel spatial atomic layer deposition (ALD) process based on pneumatic transport of nanoparticle agglomerates. Nanoclusters of platinum (Pt) of ∼1 nm diameter are deposited onto titania (TiO{sub 2}) P25 nanoparticles resulting to a continuous production of an active photocatalyst (0.12–0.31 wt. % of Pt) at a rate of about 1 g min{sup −1}. Tuning the precursor injection velocity (10–40 m s{sup −1}) enhances the contact between the precursor and the pneumatically transported support flows. Decreasing the chemisorption temperature (from 250 to 100 °C) results in more uniform distribution of the Pt nanoclusters as it decreases the reaction rate as compared to the rate of diffusion into the nanoparticle agglomerates. Utilizing this photocatalyst in the oxidation reaction of Acid Blue 9 showed a factor of five increase of the photocatalytic activity compared to the native P25 nanoparticles. The use of spatial particle ALD can be further expanded to deposition of nanoclusters on porous, micron-sized particles and to the production of core–shell nanoparticles enabling the robust and scalable manufacturing of nanostructured powders for catalysis and other applications.

  16. Periodic oxidation for fabricating titanium oxynitride thin films via atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Iwashita, Shinya, E-mail: shinya.iwashita@tel.com; Aoyama, Shintaro; Nasu, Masayuki; Shimomura, Kouji; Noro, Naotaka; Hasegawa, Toshio; Akasaka, Yasushi [SPE Core Technology Development Department, Tokyo Electron Yamanashi Ltd., 50 Mitsuzawa, Hosaka-cho, 407-0192 Nirasaki (Japan); Miyashita, Kohei [Leading Edge Process Development Center, Tokyo Electron Ltd., 650 Mitsuzawa, Hosaka-cho, 407-0192 Nirasaki (Japan)

    2016-01-15

    This paper demonstrates thermal atomic layer deposition (ALD) combined with periodic oxidation for synthesizing titanium oxynitride (TiON) thin films. The process used a typical ALD reactor for the synthesis of titanium nitride (TiN) films wherein oxygen was supplied periodically between the ALD-TiN cycles. The great advantage of the process proposed here was that it allowed the TiN films to be oxidized efficiently. Also, a uniform depth profile of the oxygen concentration in the films could be obtained by tuning the oxidation conditions, allowing the process to produce a wide variety of TiON films. The resistivity measurement is a convenient method to confirm the reproducibility of metal film fabrication but may not be applicable for TiON films depending upon the oxidation condition because the films can easily turn into insulators when subjected to periodic oxidation. Therefore, an alternative reproducibility confirmation method was required. In this study, spectroscopic ellipsometry was applied to monitor the variation of TiON films and was able to detect changes in film structures such as conductor–insulator transitions in the TiON films.

  17. Thermal conductivity of amorphous Al2O3/TiO2 nanolaminates deposited by atomic layer deposition.

    Science.gov (United States)

    Ali, Saima; Juntunen, Taneli; Sintonen, Sakari; Ylivaara, Oili M E; Puurunen, Riikka L; Lipsanen, Harri; Tittonen, Ilkka; Hannula, Simo-Pekka

    2016-11-04

    The thermophysical properties of Al2O3/TiO2 nanolaminates deposited by atomic layer deposition (ALD) are studied as a function of bilayer thickness and relative TiO2 content (0%-100%) while the total nominal thickness of the nanolaminates was kept at 100 nm. Cross-plane thermal conductivity of the nanolaminates is measured at room temperature using the nanosecond transient thermoreflectance method. Based on the measurements, the nanolaminates have reduced thermal conductivity as compared to the pure amorphous thin films, suggesting that interfaces have a non-negligible effect on thermal transport in amorphous nanolaminates. For a fixed number of interfaces, we find that approximately equal material content of Al2O3 and TiO2 produces the lowest value of thermal conductivity. The thermal conductivity reduces with increasing interface density up to 0.4 nm(-1), above which the thermal conductivity is found to be constant. The value of thermal interface resistance approximated by the use of diffuse mismatch model was found to be 0.45 m(2) K GW(-1), and a comparative study employing this value supports the interpretation of non-negligible interface resistance affecting the overall thermal conductivity also in the amorphous limit. Finally, no clear trend in thermal conductivity values was found for nanolaminates grown at different deposition temperatures, suggesting that the temperature in the ALD process has a non-trivial while modest effect on the overall thermal conductivity in amorphous nanolaminates.

  18. Thermal conductivity of amorphous Al2O3/TiO2 nanolaminates deposited by atomic layer deposition

    Science.gov (United States)

    Ali, Saima; Juntunen, Taneli; Sintonen, Sakari; Ylivaara, Oili M. E.; Puurunen, Riikka L.; Lipsanen, Harri; Tittonen, Ilkka; Hannula, Simo-Pekka

    2016-11-01

    The thermophysical properties of Al2O3/TiO2 nanolaminates deposited by atomic layer deposition (ALD) are studied as a function of bilayer thickness and relative TiO2 content (0%-100%) while the total nominal thickness of the nanolaminates was kept at 100 nm. Cross-plane thermal conductivity of the nanolaminates is measured at room temperature using the nanosecond transient thermoreflectance method. Based on the measurements, the nanolaminates have reduced thermal conductivity as compared to the pure amorphous thin films, suggesting that interfaces have a non-negligible effect on thermal transport in amorphous nanolaminates. For a fixed number of interfaces, we find that approximately equal material content of Al2O3 and TiO2 produces the lowest value of thermal conductivity. The thermal conductivity reduces with increasing interface density up to 0.4 nm-1, above which the thermal conductivity is found to be constant. The value of thermal interface resistance approximated by the use of diffuse mismatch model was found to be 0.45 m2 K GW-1, and a comparative study employing this value supports the interpretation of non-negligible interface resistance affecting the overall thermal conductivity also in the amorphous limit. Finally, no clear trend in thermal conductivity values was found for nanolaminates grown at different deposition temperatures, suggesting that the temperature in the ALD process has a non-trivial while modest effect on the overall thermal conductivity in amorphous nanolaminates.

  19. An Internal ALD-Based High Voltage Divider and Signal Circuit for MCP-based Photodetectors

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Bernhard W.; Elagin, Andrey; Elam, Jeffrey W.; Frisch, Henry J.; Genat, Jean-Francois; Gregar, Joseph S.; Mane, Anil U.; Minot, Michael J.; Northrup, Richard; Obaid, Razib; Oberla, Eric; Alexander, Vostrikov; Wetstein, Matthew

    2015-04-21

    We describe a pin-less design for the high voltage (HV) resistive divider of the all-glass LAPPD (TM) 8 in,square thin photodetector module. The divider, which distributes high voltage applied to the photocathode to the two micro-channel plates (MCPs) that constitute the amplification stage, is comprised of the two MCPs and three glass mechanical spacers, each of which is coated with a resistive layer using atomic layer deposition (ALD). The three glass grid spacers and the two MCPs form a continuous resistive path between cathode and anode, with the voltages across the MCPs and the spacers determined by the resistance of each. High voltage is applied on an external tab on the top glass window that connects to the photocathode through the metal seal. The DC ground is supplied by microstrips on the bottom glass plate that form the high-bandwidth anode. The microstrips exit the package through the glass-frit seal of the anode base-plate and the package sidewall. The divider is thus completely internal, with no HV pins penetrating the low-profile flat glass package. Measurements of the performance of the divider are presented for the 8 in.-square MCP and spacer package in a custom test fixture and for an assembled externally pumped LAPPD (TM) prototype with an aluminum photocathode. (C) 2015 Elsevier B.V. All rights reserved.

  20. Influence of transparent conductive oxides on passivation of a-Si:H/c-Si heterojunctions as studied by atomic layer deposited Al-doped ZnO

    Science.gov (United States)

    Macco, B.; Deligiannis, D.; Smit, S.; van Swaaij, R. A. C. M. M.; Zeman, M.; Kessels, W. M. M.

    2014-12-01

    In silicon heterojunction solar cells, the main opportunities for efficiency gain lie in improvements of the front-contact layers. Therefore, the effect of transparent conductive oxides (TCOs) on the a-Si:H passivation performance has been investigated for Al-doped zinc oxide (ZnO:Al) layers made by atomic layer deposition (ALD). It is shown that the ALD process, as opposed to sputtering, does not impair the chemical passivation. However, the field-effect passivation is reduced by the ZnO:Al. The resulting decrease in low injection-level lifetime can be tuned by changing the ZnO:Al doping level (carrier density = 7 × 1019-7 × 1020 cm-3), which is explained by a change in the TCO workfunction. Additionally, it is shown that a ˜10-15 nm ALD ZnO:Al layer is sufficient to mitigate damage to the a-Si:H by subsequent sputtering, which is correlated to ALD film closure at this thickness.

  1. A parametric simulation study for solvent co-injection process in bitumen deposits

    Energy Technology Data Exchange (ETDEWEB)

    Yazdani, A.; Alvestad, J.; Kjonsvik, D.; Gilje, E.; Kowalewski, E. [Statoil Canada (Canada)

    2011-07-01

    The extraction of very large Canadian extra heavy oil and bitumen deposits is facing major challenges, such as energy requirements and access to sustainable water resources. Steam assisted gravity drainage (SAGD) is the most common commercial in-situ recovery process used for the extraction but it has many associated economic and environmental challenges. Moreover, current knowledge of the fundamental physics and mechanics involved in the process is not satisfactory. This paper presents a parametric simulation study for a solvent co-injection (SCI) process in bitumen deposits. This process has the potential to improve the efficiency of steam processes as well as to reduce energy use and CO2 emissions. The study contributes to further understanding of the development process. Several operational and geological parameters were evaluated to assess their impact on SAGD operations. The results demonstrated that the basis for selecting the optimum solvent should not only be mobility improvement capability but should also include other operational and geological conditions.

  2. Properties of Aluminum Deposited by a High-Velocity Oxygen-Fueled Process

    Energy Technology Data Exchange (ETDEWEB)

    Chow, R; Decker, T A; Gansert, R V; Gansert, D; Lee, D

    2001-06-12

    Aluminum coatings deposited by a HVOF process have been demonstrated and relevant coating properties evaluated according to two deposition parameters, the spray distance and the oxygen-to-fuel flow ratio. The coating porosity, surface roughness, and microhardness are measured. The coating properties are fairly insensitive to spray distance, the distance between the nozzle and the workpiece, and fuel ratios, the oxygen-to-fuel flow. Increasing the fuel content does appear to improve the process productivity in terms of surface roughness. Minimization of nozzle loading is discussed.

  3. Highly stable Na2/3 (Mn0.54 Ni0.13 Co0.13 )O2 cathode modified by atomic layer deposition for sodium-ion batteries.

    Science.gov (United States)

    Kaliyappan, Karthikeyan; Liu, Jian; Lushington, Andrew; Li, Ruying; Sun, Xueliang

    2015-08-10

    For the first time, atomic layer deposition (ALD) of Al2 O3 was adopted to enhance the cyclic stability of layered P2-type Na2/3 (Mn0.54 Ni0.13 Co0.13 )O2 (MNC) cathodes for use in sodium-ion batteries (SIBs). Discharge capacities of approximately 120, 123, 113, and 105 mA h g(-1) were obtained for the pristine electrode and electrodes coated with 2, 5, and 10 ALD cycles, respectively. All electrodes were cycled at the 1C discharge current rate for voltages between 2 and 4.5 V in 1 M NaClO4 electrolyte. Among the electrodes tested, the Al2 O3 coating from 2 ALD cycles (MNC-2) exhibited the best electrochemical stability and rate capability, whereas the electrode coated by 10 ALD cycles (MNC-10) displayed the highest columbic efficiency (CE), which exceeded 97 % after 100 cycles. The enhanced electrochemical stability observed for ALD-coated electrodes could be a result of the protection effects and high band-gap energy (Eg =9.00 eV) of the Al2 O3 coating layer. Additionally, the metal-oxide coating provides structural stability against mechanical stresses occurring during the cycling process. The capacity, cyclic stability, and rate performance achieved for the MNC electrode coated with 2 ALD cycles of Al2 O3 reveal the best results for SIBs. This study provides a promising route toward increasing the stability and CE of electrode materials for SIB application.

  4. Fabrication of AlN/BN bishell hollow nanofibers by electrospinning and atomic layer deposition

    Directory of Open Access Journals (Sweden)

    Ali Haider

    2014-09-01

    Full Text Available Aluminum nitride (AlN/boron nitride (BN bishell hollow nanofibers (HNFs have been fabricated by successive atomic layer deposition (ALD of AlN and sequential chemical vapor deposition (CVD of BN on electrospun polymeric nanofibrous template. A four-step fabrication process was utilized: (i fabrication of polymeric (nylon 6,6 nanofibers via electrospinning, (ii hollow cathode plasma-assisted ALD of AlN at 100 °C onto electrospun polymeric nanofibers, (iii calcination at 500 °C for 2 h in order to remove the polymeric template, and (iv sequential CVD growth of BN at 450 °C. AlN/BN HNFs have been characterized for their chemical composition, surface morphology, crystal structure, and internal nanostructure using X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and selected area electron diffraction. Measurements confirmed the presence of crystalline hexagonal BN and AlN within the three dimensional (3D network of bishell HNFs with relatively low impurity content. In contrast to the smooth surface of the inner AlN layer, outer BN coating showed a highly rough 3D morphology in the form of BN nano-needle crystallites. It is shown that the combination of electrospinning and plasma-assisted low-temperature ALD/CVD can produce highly controlled multi-layered bishell nitride ceramic hollow nanostructures. While electrospinning enables easy fabrication of nanofibrous template, self-limiting reactions of plasma-assisted ALD and sequential CVD provide control over the wall thicknesses of AlN and BN layers with sub-nanometer accuracy.

  5. The effect of process variables on microstructure in laser-deposited materials

    Science.gov (United States)

    Bontha, Srikanth

    Laser deposition of titanium alloys is under consideration for aerospace applications, which require the consistent control of microstructure and resulting mechanical properties. To date, only limited experimental data exists to link deposition process variables (e.g., laser power and velocity) to resulting microstructure (e.g., grain size and morphology) in laser-deposited materials, and suitable microstructures have typically been obtained only by trial and error. In addition, it is unclear whether knowledge based on small-scale laser deposition processes (e.g., LENS(TM)) can be applied to large-scale (higher power) processes currently under development for commercial applications. Therefore, simulation-based methods are needed to predict the effects of process variables and size-scale on microstructure in laser-deposited titanium and other aerospace materials. The ability to predict and control microstructure in laser deposition processes requires an understanding of the thermal conditions at the onset of solidification. The focus of this work is the development of thermal process maps relating solidification cooling rate and thermal gradient (the key parameters controlling microstructure) to laser deposition process variables (laser power and velocity). The approach employs the well-known Rosenthal solution for a moving point heat source traversing an infinite substrate. Cooling rates and thermal gradients at the onset of solidification are numerically extracted from the Rosenthal solution throughout the depth of the melt pool, and dimensionless process maps are presented for both 2-D thin-wall and bulky 3-D geometries. Results for both small-scale (LENS(TM)) and large-scale (higher power) processes are plotted on solidification maps for predicting trends in grain morphology in laser-deposited Ti-6Al-4V. Although the Rosenthal predictions neglect the nonlinear effects of temperature-dependent properties and latent heat of transformation, a comparison with 2-D

  6. Mixing ALD/MLD-grown ZnO and Zn-4-aminophenol layers into various thin-film structures.

    Science.gov (United States)

    Sundberg, Pia; Sood, Anjali; Liu, Xuwen; Karppinen, Maarit

    2013-11-14

    Building 2D inorganic-organic hybrids by combining inorganic and organic constituents with molecular-layer precision is an attractive approach to fabricate novel materials with a tailored combination of properties from both entities. Here we demonstrate the potential of the combined atomic and molecular layer deposition (ALD/MLD) technique for the state-of-the-art synthesis of such materials and to fabricate both homogeneous thin-film mixtures and nanolaminates of ZnO and the Zn-4-aminophenol inorganic-organic hybrid. The thin films are deposited by varying the number of precursor cycles during the depositions. Diethyl zinc and 4-aminophenol (AP) are used as precursors for the Zn-AP hybrid depositions, and diethyl zinc and water for the ZnO depositions. The characterization of the mixed Zn-AP and ZnO films reveals that crystallinity, density, surface roughness, chemical stability, hardness and contact modulus are sensitively altered by even a minor insertion of Zn-AP hybrid into the ZnO structure. Fabrication of Zn-AP + ZnO nanolaminates with different thicknesses of the Zn-AP and ZnO layers provides us with an even better way to control the hardness and contact modulus, and also to enhance the chemical stability of the films.

  7. ALD grown nanostructured ZnO thin films: Effect of substrate temperature on thickness and energy band gap

    Directory of Open Access Journals (Sweden)

    Javed Iqbal

    2016-10-01

    Full Text Available Nanostructured ZnO thin films with high transparency have been grown on glass substrate by atomic layer deposition at various temperatures ranging from 100 °C to 300 °C. Efforts have been made to observe the effect of substrate temperature on the thickness of the deposited thin films and its consequences on the energy band gap. A remarkably high growth rate of 0.56 nm per cycle at a substrate temperature of 200 °C for ZnO thin films have been achieved. This is the maximum growth rate for ALD deposited ZnO thin films ever reported so far to the best of our knowledge. The studies of field emission scanning electron microscopy and X-ray diffractometry patterns confirm the deposition of uniform and high quality nanosturtured ZnO thin films which have a polycrystalline nature with preferential orientation along (100 plane. The thickness of the films deposited at different substrate temperatures was measured by ellipsometry and surface profiling system while the UV–visible and photoluminescence spectroscopy studies have been used to evaluate the optical properties of the respective thin films. It has been observed that the thickness of the thin film depends on the substrate temperatures which ultimately affect the optical and structural parameters of the thin films.

  8. Characterization of hafnium oxide resistive memory layers deposited on copper by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, B.D.; Bishop, S.M. [SUNY College of Nanoscale Science and Engineering, 255 Fuller Road, Albany, NY 12203 (United States); Leedy, K.D. [Air Force Research Laboratory, 2241 Avionics Circle, Wright Patterson Air Force Base, Dayton, OH 45433 (United States); Cady, N.C., E-mail: ncady@albany.edu [SUNY College of Nanoscale Science and Engineering, 255 Fuller Road, Albany, NY 12203 (United States)

    2014-07-01

    Hafnium oxide-based resistive memory devices have been fabricated on copper bottom electrodes. The HfO{sub x} active layers in these devices were deposited by atomic layer deposition (ALD) at 250 °C with tetrakis(dimethylamido)hafnium(IV) as the metal precursor and an O{sub 2} plasma as the reactant. Depth profiles of the HfO{sub x} by X-ray photoelectron spectroscopy and secondary ion mass spectroscopy revealed a copper concentration on the order of five atomic percent throughout the HfO{sub x} film. In addition to the Cu doped HfO{sub x}, a thin layer (20 nm) of Cu{sub x}O is present at the surface. This surface layer is believed to have formed during the ALD process, and greatly complicates the analysis of the switching mechanism. The resistive memory structures fabricated from the ALD HfO{sub x} exhibited non-polar resistive switching, independent of the top metal electrode (Ni, Pt, Al, Au). Resistive switching current voltage (I–V) curves were analyzed using Schottky emission and ionic hopping models to gain insight into the physical mechanisms underpinning the device behavior. During the forming process it was determined that, at voltages in excess of 2.5 V, an ionic hopping model is in good agreement with the I–V data. The extracted ion hopping distance ∼ 4 Å was within the range of interatomic spacing of HfO{sub 2} during the forming process consistent with ionic motion of Cu{sup 2+} ions. Lastly the on state I–V data was dominated at larger voltages by Schottky emission with an estimated barrier height of ∼ 0.5 eV and a refractive index of 2.59. The consequence of the Schottky emission analysis indicates the on state resistance to be a product of a Pt/Cu{sub 2}O/Cu filament(s)/Cu{sub 2}O/Cu structure. - Highlights: • HfO{sub 2} was grown via atomic layer deposition at 250 and 100 °C on Cu substrates. • A Cu{sub 2}O surface layer and Cu doping were observed in post-deposition of HfO{sub 2}. • Resistive memory devices were fabricated and

  9. Deposition of wear-resistant steel surfaces by the plasma rotating electrode coating process

    Science.gov (United States)

    Kim, Michael Robert

    A high-deposition rate thermal spray method was investigated for the purpose of coating aluminum cylinder bores with a wear resistant surface. This method, the plasma rotating electrode coating system (PROTEC) utilized transferred-arc melting of a rapidly rotating consumable electrode to create a droplet stream via centrifugal atomization. A cylindrical substrate was placed around the rotating rod, in the flight path of the droplets, to deposit a coating onto the internal surface of the cylinder. Selected coatings of 1045 steel deposited by the PROTEC coating method exhibited lower wear loss in lubricated sliding than wire-arc sprayed carbon steel coatings and gray cast iron. Splat cohesion was shown to be a significant factor in the wear resistance of PROTEC coatings. The relationship between deposition enthalpy and cooling rate of the coating was found to have the greatest effect on coating microstructure, and the coating cohesion. The most rapidly solidified coatings showed inferior splat cohesion in comparison to coatings that cooled more slowly. The increase in splat cohesion with decreased cooling rate was accompanied by the formation of a directionally oriented coating microstructure, likely formed during cellular solidification of the coating. A model describing the thermal state of the deposition process was used to predict the deposition conditions that would result in a cellular structure, and the level of splat cohesion required to produce a wear resistant coating.

  10. A discrete element based simulation framework to investigate particulate spray deposition processes

    KAUST Repository

    Mukherjee, Debanjan

    2015-06-01

    © 2015 Elsevier Inc. This work presents a computer simulation framework based on discrete element method to analyze manufacturing processes that comprise a loosely flowing stream of particles in a carrier fluid being deposited on a target surface. The individual particulate dynamics under the combined action of particle collisions, fluid-particle interactions, particle-surface contact and adhesive interactions is simulated, and aggregated to obtain global system behavior. A model for deposition which incorporates the effect of surface energy, impact velocity and particle size, is developed. The fluid-particle interaction is modeled using appropriate spray nozzle gas velocity distributions and a one-way coupling between the phases. It is found that the particle response times and the release velocity distribution of particles have a combined effect on inter-particle collisions during the flow along the spray. It is also found that resolution of the particulate collisions close to the target surface plays an important role in characterizing the trends in the deposit pattern. Analysis of the deposit pattern using metrics defined from the particle distribution on the target surface is provided to characterize the deposition efficiency, deposit size, and scatter due to collisions.

  11. Solution processed deposition of electron transport layers on perovskite crystal surface-A modeling based study

    Science.gov (United States)

    Mortuza, S. M.; Taufique, M. F. N.; Banerjee, Soumik

    2017-02-01

    The power conversion efficiency (PCE) of planar perovskite solar cells (PSCs) has reached up to ∼20%. However, structural and chemicals defects that lead to hysteresis in the perovskite based thin film pose challenges. Recent work has shown that thin films of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) deposited on the photo absorption layer, using solution processing techniques, minimize surface pin holes and defects thereby increasing the PCE. We developed and employed a multiscale model based on molecular dynamics (MD) and kinetic Monte Carlo (kMC) to establish a relationship between deposition rate and surface coverage on perovskite surface. The MD simulations of PCBMs dispersed in chlorobenzene, sandwiched between (110) perovskite substrates, indicate that PCBMs are deposited through anchoring of the oxygen atom of carbonyl group to the exposed lead (Pb) atom of (110) perovskite surface. Based on rates of distinct deposition events calculated from MD, kMC simulations were run to determine surface coverage at much larger time and length scales than accessible by MD alone. Based on the model, a generic relationship is established between deposition rate of PCBMs and surface coverage on perovskite crystal. The study also provides detailed insights into the morphology of the deposited film.

  12. Novel electroless copper deposition on carbon fibers with environmentally friendly processes.

    Science.gov (United States)

    Byeon, Jeong Hoon; Kim, Jang-Woo

    2010-08-15

    A novel electroless deposition (ELD) of copper (Cu) on carbon fibers (CFs) with environmentally friendly processes, silver (Ag) aerosol activation and subsequent nonformaldehyde Cu ELD, was developed. Spark-generated Ag aerosol nanoparticles (approximately 10 nm in mode diameter) were deposited (48.4 microg Ag/g CF in activation intensity) onto the surfaces of CFs. After annealing (at 220 degrees C in a nitrogen atmosphere), the catalytically activated CFs were placed into a solution for Cu ELD (at 82 degrees C). Homogeneous Cu coating (approximately 5.1 nm/min) on CFs was achieved with 90 min of deposition and the corresponding mass deposition rate and Cu grain size for 30-90 min of deposition had ranges of 0.25-1.14 mg Cu/g CF-min and 14.8-37.2 nm, respectively. The porosity of CFs decreased by depositing the Cu for 30-90 min, and the specific surface area and pore volume of CFs decreased from 1536 to 1399 m(2)/g and from 0.65 to 0.57 cm(3)/g, respectively.

  13. Fabrication of FeSe superconducting films with chemical transport deposition process

    Science.gov (United States)

    Feng, J. Q.; Zhang, S. N.; Liu, J. X.; Hao, Q. B.; Li, C. S.; Zhang, P. X.

    2017-07-01

    FeSe Superconducting films were fabricated with a chemical transport deposition process. During the fabrication process, Fe foils were adopted as substrates and Se powders were put at one end of the tube furnace. During the heating process, Se powders were vaporized, and vaporized atoms were carried by Ar flow and deposited on the Fe substrates. With a heat treatment process under proper temperature, superconducting tetragonal β-FeSe phase can be obtained. The effects of key parameters, including the sintering temperatures and the distances between Fe substrates and Se source on the phase composition and morphology of the obtained films were systematically investigated. The superconducting transition temperature of 7.8 K was obtained on the optimized film. By further optimization of the heat treatment process, it is promising to fabricate FeSe films with higher superconducting phase content and better superconducting properties.

  14. Metallorganic chemical vapor deposition and atomic layer deposition approaches for the growth of hafnium-based thin films from dialkylamide precursors for advanced CMOS gate stack applications

    Science.gov (United States)

    Consiglio, Steven P.

    To continue the rapid progress of the semiconductor industry as described by Moore's Law, the feasibility of new material systems for front end of the line (FEOL) process technologies needs to be investigated, since the currently employed polysilicon/SiO2-based transistor system is reaching its fundamental scaling limits. Revolutionary breakthroughs in complementary-metal-oxide-semiconductor (CMOS) technology were recently announced by Intel Corporation and International Business Machines Corporation (IBM), with both organizations revealing significant progress in the implementation of hafnium-based high-k dielectrics along with metal gates. This announcement was heralded by Gordon Moore as "...the biggest change in transistor technology since the introduction of polysilicon gate MOS transistors in the late 1960s." Accordingly, the study described herein focuses on the growth of Hf-based dielectrics and Hf-based metal gates using chemical vapor-based deposition methods, specifically metallorganic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD). A family of Hf source complexes that has received much attention recently due to their desirable properties for implementation in wafer scale manufacturing is the Hf dialkylamide precursors. These precursors are room temperature liquids and possess sufficient volatility and desirable decomposition characteristics for both MOCVD and ALD processing. Another benefit of using these sources is the existence of chemically compatible Si dialkylamide sources as co-precursors for use in Hf silicate growth. The first part of this study investigates properties of MOCVD-deposited HfO2 and HfSixOy using dimethylamido Hf and Si precursor sources using a customized MOCVD reactor. The second part of this study involves a study of wet and dry surface pre-treatments for ALD growth of HfO2 using tetrakis(ethylmethylamido)hafnium in a wafer scale manufacturing environment. The third part of this study is an investigation of

  15. Microstructural Evolution and Mechanical Properties of Inconel 625 Alloy during Pulsed Plasma Arc Deposition Process

    Institute of Scientific and Technical Information of China (English)

    Fujia Xu; Yaohui Lv; Yuxin Liu; Fengyuan Shu; Peng He; Binshi Xu

    2013-01-01

    Pulsed plasma arc deposition (PPAD),which combines pulsed plasma cladding with rapid prototyping,is a promising technology for manufacturing near net shape components due to its superiority in cost and convenience of processing.In the present research,PPAD was successfully used to fabricate the Ni-based superalloy Inconel 625 components.The microstructures and mechanical properties of deposits were investigated by scanning electron microscopy (SEM),optical microscopy (OM),transmission electron microscopy (TEM) with energy dispersive spectrometer (EDS),microhardness and tensile testers.It was found that the as-deposited structure exhibited homogenous columnar dendrite structure,which grew epitaxially along the deposition direction.Moreover,some intermetallic phases such as Laves phase,minor MC (NbC,TiC) carbides and needle-like δ-Ni3Nb were observed in γ-Ni matrix.Precipitation mechanism and distribution characteristics of these intermetallic phases in the as-deposited 625 alloy sample were analyzed.In order to evaluate the mechanical properties of the deposits,microhardness was measured at various location (including transverse plane and longitudinal plane).The results revealed hardness was in the range of 260-285 HVo.2.In particular,microhardness at the interface region between two adjacent deposited layers was slightly higher than that at other regions due to highly refined structure and the disperse distribution of Laves particles.Finally,the influence of precipitation phases and fabrication strategies on the tensile properties of the as-deposited samples was investigated.The failure modes of the tensile specimens were analyzed with fractography.

  16. Evaluation of Mineral Deposits Along the Little Wind River, Riverton, WY, Processing Site

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Sam [Navarro Research and Engineering, Oak Ridge, TN (United States); Dam, Wiliam [US Department of Energy, Washington, DC (United States). Office of Legacy Management

    2014-12-01

    In 2012, the U.S.Department of Energy (DOE) began reassessing the former Riverton, Wyoming, Processing Site area for potential contaminant sources impacting groundwater. A flood in 2010 along the Little Wind River resulted in increases in groundwater contamination (DOE 2013).This investigation is a small part of continued efforts by DOE and other stakeholders to update human health and ecological risk assessments, to make a comprehensive examination of all exposure pathways to ensure that the site remains protective through established institutional controls. During field inspections at the Riverton Site in 2013, a white evaporitic mineral deposit was identified along the bank of the Little Wind River within the discharge zone of the groundwater contamination plume. In December 2013, Savannah River National Laboratory (SRNL) personnel collected a sample for analysis by X-ray fluorescence (Figure 1 shows the type of material sampled). The sample had a uranium concentration of approximately 64 to 73 parts per million. Although the uranium in this mineral deposit is within the expected range for evaporatic minerals in the western United States (SRNL 2014), DOE determined that additional assessment of the mineral deposit was warranted. In response to the initial collection and analysis of a sample of the mineral deposit, DOE developed a work plan (Work Plan to Sample Mineral Deposits Along the Little Wind River, Riverton, Wyoming, Processing Site [DOE 2014]) to further define the extent of these mineral deposits and the concentration of the associated contaminants (Appendix A). The work plan addressed field reconnaissance, mapping, sampling, and the assessment of risk associated with the mineral deposits adjacent to the Little Wind River.

  17. Passivation of type II InAs/GaSb superlattice photodetectors with atomic layer deposited Al2O3

    Science.gov (United States)

    Salihoglu, Omer; Muti, Abdullah; Kutluer, Kutlu; Tansel, Tunay; Turan, Rasit; Kocabas, Coskun; Aydinli, Atilla

    2012-06-01

    We have achieved significant improvement in the electrical performance of the InAs/GaSb midwave infrared photodetector (MWIR) by using atomic layer deposited (ALD) aluminium oxide (Al2O3) as a passivation layer. Plasma free and low operation temperature with uniform coating of ALD technique leads to a conformal and defect free coverage on the side walls. This conformal coverage of rough surfaces also satisfies dangling bonds more efficiently while eliminating metal oxides in a self cleaning process of the Al2O3 layer. Al2O3 passivated and unpassivated diodes were compared for their electrical and optical performances. For passivated diodes the dark current density was improved by an order of magnitude at 77 K. The zero bias responsivity and detectivity was 1.33 A/W and 1.9 x 1013 Jones, respectively at 4 μm and 77 K. Quantum efficiency (QE) was determined as %41 for these detectors.

  18. Study of GaN MOS-HEMT using ultrathin Al2O3 dielectric grown by atomic layer deposition

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    We report on a GaN metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT) using atomic-layer deposited (ALD) Al2O3 as the gate dielectric. Through further decreasing the thickness of the gate oxide to 3.5 nm and optimizing the device fabrication process,a device with maximum transconductance of 150 mS/mm was produced. The drain current of this 0.8 μm gate-length MOS-HEMT could reach 800 mA/mm at +3.0 V gate bias. Compared to a conventional AlGaN/GaN HEMT of similar design,better interface property,lower leakage current,and smaller capacitance-voltage (C-V) hysteresis were obtained,and the superiority of this MOS-HEMT device structure with ALD Al2O3 gate dielectric was exhibited.

  19. Study of GaN MOS-HEMT using ultrathin Al2O3 dielectric grown by atomic layer deposition

    Institute of Scientific and Technical Information of China (English)

    YUE YuanZheng; HAO Yue; FENG Qian; ZHANG JinCheng; MA XiaoHua; NI JinYu

    2009-01-01

    We report on a GaN metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT) using atomic-layer deposited (ALD) Al2O3 as the gate dielectric. Through further decreasing the thickness of the gate oxide to 3.5 nm and optimizing the device fabrication process, a device with maximum transconductance of 150 mS/mm was produced. The drain current of this 0.8 μm gate-length MOS-HEMT could reach 800 mA/mm at +3.0 V gate bias. Compared to a conventional AIGaN/GaN HEMT of similar design, better interface property, lower leakage current, and smaller capacitance-voltage (C-V) hysteresis were obtained, and the superiority of this MOS-HEMT device structure with ALD Al2O3 gate dielectric was exhibited.

  20. Biofunctionalization of carbon nanotubes/chitosan hybrids on Ti implants by atom layer deposited ZnO nanostructures

    Science.gov (United States)

    Zhu, Yizhou; Liu, Xiangmei; Yeung, Kelvin W. K.; Chu, Paul K.; Wu, Shuilin

    2017-04-01

    One-dimensional (1D) nanostructures of ZnO using atomic layer deposition (ALD) on chitosan (CS) modified carbon nanotubes (CNTs) were first introduced onto the surfaces of biomedical implants. When the content of ZnO is not sufficient, CNTs can strengthen the antibacterial activity against E. coli and S. aureus by 8% and 39%, respectively. CS can improve the cytocompatibility of CNTs and ZnO. The amount of Zn content can be controlled by changing the cycling numbers of ALD processes. This hybrid coating can not only endow medical implants with high self-antibacterial efficacy against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) of over 73% and 98%, respectively, but also regulate the proliferation and osteogenic differentiation of osteoblasts by controlling the amount of ZnO.

  1. Ru nanostructure fabrication using an anodic aluminum oxide nanotemplate and highly conformal Ru atomic layer deposition.

    Science.gov (United States)

    Kim, Woo-Hee; Park, Sang-Joon; Son, Jong-Yeog; Kim, Hyungjun

    2008-01-30

    We fabricated metallic nanostructures directly on Si substrates through a hybrid nanoprocess combining atomic layer deposition (ALD) and a self-assembled anodic aluminum oxide (AAO) nanotemplate. ALD Ru films with Ru(DMPD)(EtCp) as a precursor and O(2) as a reactant exhibited high purity and low resistivity with negligible nucleation delay and low roughness. These good growth characteristics resulted in the excellent conformality for nanometer-scale vias and trenches. Additionally, AAO nanotemplates were fabricated directly on Si and Ti/Si substrates through a multiple anodization process. AAO nanotemplates with various hole sizes (30-100 nm) and aspect ratios (2:1-20:1) were fabricated by controlling the anodizing process parameters. The barrier layers between AAO nanotemplates and Si substrates were completely removed by reactive ion etching (RIE) using BCl(3) plasma. By combining the ALD Ru and the AAO nanotemplate, Ru nanostructures with controllable sizes and shapes were prepared on Si and Ti/Si substrates. The Ru nanowire array devices as a platform for sensor devices exhibited befitting properties of good ohmic contact and high surface/volume ratio.

  2. Active soft solder deposition by magnetron-sputter-ion-plating (MSIP)-PVD-process

    Energy Technology Data Exchange (ETDEWEB)

    Lugscheider, E.; Bobzin, K.; Erdle, A

    2004-01-30

    In different technical areas micro electro mechanical systems (M.E.M.S.), e.g. micro pumps, micro sensors, actuators and micro dosage systems are in use today. The components of these M.E.M.S. consist of various materials, which have to be joined. To join materials like ceramics, plastics or metals to a hybrid M.E.M.S., established joining technologies have to be adjusted. For the assembling and mounting of temperature sensible micro components, a low temperature joining process, e.g. transient liquid phase (TLP) bonding or an active soft soldering process can be performed. In this article the deposition of a low melting active soft solder by magnetron-sputter (MS)-PVD deposition with an active substrate cooling will be presented. The substrate temperatures were set and controlled by an additional cooling unit, which was integrated into the sputtering facility. In the performed experiments a substrate temperature range from -40 to +20 deg. C was investigated. The effects of these different substrate temperatures to the microstructure and the soldering suitability of the solder system were investigated by scanning electron microscopy (SEM), nanoindentation and soldering tests. The chemical composition of the deposited solder systems was examined by glow discharge optical spectroscopy (GDOS)-analysis. As a suitable substrate temperature range for deposition -10 to -20 deg. C was detected. Solder systems deposited in this temperature range showed good solder abilities.

  3. Magnetic properties related to hydrothermal alteration processes at the Escondida porphyry copper deposit, northern Chile

    Science.gov (United States)

    Riveros, K.; Veloso, E.; Campos, E.; Menzies, A.; Véliz, W.

    2014-08-01

    Fluid-rock interaction related to the circulation of hydrothermal fluids can strongly modify the physicochemical properties of wall rocks in porphyry Cu deposits. These processes can also produce compositional and textural changes in ferromagnetic minerals, which can be quantified using magnetic methods. In the Escondida porphyry Cu deposit of northern Chile, each hydrothermally altered lithology is characterized by a discrete assemblage of Fe-Ti oxide minerals. These minerals have distinctive bulk magnetic susceptibility ( K bulk), temperature-dependent magnetic susceptibility, and magnetic hysteresis parameters. Selectively altered rocks (i.e., potassic and chloritic alteration types) exhibit the highest K bulk values (>3.93 × 10-3 SI units), and their hysteresis parameters indicate multidomain magnetic mineral behavior. This suggests that these rocks are composed of the coarsest magnetic grain sizes within the deposit. Optical analyses and susceptibility-temperature curves confirm that the magnetic signals in selectively altered rocks are mainly carried by secondary magnetite. In contrast, pervasively altered rocks (i.e., quartz-sericite and argillic alteration types) exhibit low K bulk values (hydrothermal alteration processes, Fe-Ti oxide minerals, and magnetic properties of the wall rock in the Escondida deposit. These magnetic methods can be considered a sensitive and efficient petrophysical tool for the identification and semi-quantification of alteration assemblages, and facilitating the recognition and mapping of discrete hydrothermal zones during exploration and operation of porphyry Cu deposits.

  4. Basical characteristics of fluid geologic process of interlayer oxidation zone sandstone-typeuranium deposit

    Institute of Scientific and Technical Information of China (English)

    WU; BoLin; LIU; ChiYang; WANG; JianQiang

    2007-01-01

    This paper reveals the physicochemical properties such as component, formulation, genesis, tem- perature, pH, Eh, salinity and pressure of all main alteration fluid of interlayer oxidation zone sand- stone-type uranium deposits after studying the geologic process and geochemistry of internal typical sandstone-type uranium deposits such as Shihongtan deposit in the Turpan-Hami basin, 512 deposit in the Yili basin, Dongsheng deposit in the Ordos basin. The composition of fluid can be divided into two parts based on the analysis of inclusion: one can be affirmed as atmospheric water with ordinary temperature epigenesist according to the character of hydrogen and oxygen isotope of inclusion, the other is natural gas containing gaseous hydrocarbon like CH4, and CO2 as well as a little H2S, CO, H2, N2 and so on, it always contains a small quantity of hydrocarbon liquid in petroliferous basins. The fluid property of oxidation alteration zone is always oxidation alkaline, and neutrality or weak acid-weak alkaline and reducibility during the metallizing process, but at secondary reduction or deoxidization zone it becomes strong reduction alkaline. Oxygenic groundwater in the fluid is the activate and mig- ratory medium of uranium element, but the gaseous hydrocarbon like CH4 as well as H2, H2S, CO from natural gas is the important sedimentary reducer of uranium mineral; the transformation of pH,Eh in fluid environment is the main reason for the formation of uranium metallization.

  5. Optimization of Nano-Process Deposition Parameters Based on Gravitational Search Algorithm

    Directory of Open Access Journals (Sweden)

    Norlina Mohd Sabri

    2016-06-01

    Full Text Available This research is focusing on the radio frequency (RF magnetron sputtering process, a physical vapor deposition technique which is widely used in thin film production. This process requires the optimized combination of deposition parameters in order to obtain the desirable thin film. The conventional method in the optimization of the deposition parameters had been reported to be costly and time consuming due to its trial and error nature. Thus, gravitational search algorithm (GSA technique had been proposed to solve this nano-process parameters optimization problem. In this research, the optimized parameter combination was expected to produce the desirable electrical and optical properties of the thin film. The performance of GSA in this research was compared with that of Particle Swarm Optimization (PSO, Genetic Algorithm (GA, Artificial Immune System (AIS and Ant Colony Optimization (ACO. Based on the overall results, the GSA optimized parameter combination had generated the best electrical and an acceptable optical properties of thin film compared to the others. This computational experiment is expected to overcome the problem of having to conduct repetitive laboratory experiments in obtaining the most optimized parameter combination. Based on this initial experiment, the adaptation of GSA into this problem could offer a more efficient and productive way of depositing quality thin film in the fabrication process.

  6. Atomic layer deposition on porous powders with in situ gravimetric monitoring in a modular fixed bed reactor setup

    Science.gov (United States)

    Strempel, V. E.; Naumann d'Alnoncourt, R.; Driess, M.; Rosowski, F.

    2017-07-01

    A modular setup for Atomic Layer Deposition (ALD) on high-surface powder substrates in fixed bed reactors with a gravimetric in situ monitoring was developed. The design and operation are described in detail. An integrated magnetically suspended balance records mass changes during ALD. The highly versatile setup consists of three modular main units: a dosing unit, a reactor unit, and a downstream unit. The reactor unit includes the balance, a large fixed bed reactor, and a quartz crystal microbalance. The dosing unit is equipped with a complex manifold to deliver gases and gaseous reagents including three different ALD precursors, five oxidizing or reducing agents, and two purge gas lines. The system employs reactor temperatures and pressures in the range of 25-600 °C and 10-3 to 1 bar, respectively. Typically, powder batches between 100 mg and 50 g can be coated. The capabilities of the setup are demonstrated by coating mesoporous SiO2 powder with a thin AlOx (submono) layer using three cycles with trimethylaluminium and H2O. The self-limiting nature of the deposition has been verified with the in situ gravimetric monitoring and full saturation curves are presented. The process parameters were used for a scale-up in a large fixed bed reactor. The samples were analyzed with established analytics such as X-ray diffraction, N2 adsorption, transmission electron microscopy, and inductively coupled plasma optical emission spectrometry.

  7. Self-assembling Process of Alkanethiol Monolayers on Gold Surface via Underpotential Deposition

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    It was demonstrated feasible that underpotential deposition(UPD) of copper on a monolayer-modified gold substrate can be used to determine the gold electrode area. The deposition and stripping of a Cu adlayer can take place reversibly and stably at a bared or a self-assembled monolayer modified gold electrode. The growth kinetics of decanethiol/Au was also investigated via Cu UPD. The difference between the assembling kinetics determined by UPD and that by quartz crystal microbalance measurements reveals the configuration transmutation of the assembled molecules from a disordered arrangement to an ordered arrangement during the self-assembling processes.

  8. Atomic and Molecular Layer Deposition for Enhanced Lithium Ion Battery Electrodes and Development of Conductive Metal Oxide/Carbon Composites

    Science.gov (United States)

    Travis, Jonathan

    The performance and safety of lithium-ion batteries (LIBs) are dependent on interfacial processes at the positive and negative electrodes. For example, the surface layers that form on cathodes and anodes are known to affect the kinetics and capacity of LIBs. Interfacial reactions between the electrolyte and the electrodes are also known to initiate electrolyte combustion during thermal runaway events that compromise battery safety. Atomic layer deposition (ALD) and molecular layer deposition (MLD) are thin film deposition techniques based on sequential, self-limiting surface reactions. ALD and MLD can deposit ultrathin and conformal films on high aspect ratio and porous substrates such as composite particulate electrodes in lithium-ion batteries. The effects of electrode surface modification via ALD and MLD are studied using a variety of techniques. It was found that sub-nm thick coatings of Al2O 3 deposited via ALD have beneficial effects on the stability of LIB anodes and cathodes. These same Al2O3 ALD films were found to improve the safety of graphite based anodes through prevention of exothermic solid electrolyte interface (SEI) degradation at elevated temperatures. Ultrathin and conformal metal alkoxide polymer films known as "metalcones" were grown utilizing MLD techniques with trimethylaluminum (TMA) or titanium tetrachloride (TiCl4) and organic diols or triols, such as ethylene glycol (EG), glycerol (GL) or hydroquinone (HQ), as the reactants. Pyrolysis of these metalcone films under inert gas conditions led to the development of conductive metal oxide/carbon composites. The composites were found to contain sp2 carbon using micro-Raman spectroscopy in the pyrolyzed films with pyrolysis temperatures ≥ 600°C. Four point probe measurements demonstrated that the graphitic sp2 carbon domains in the metalcone films grown using GL and HQ led to significant conductivity. The pyrolysis of conformal MLD films to obtain conductive metal oxide/carbon composite films

  9. STUDY OF DYNAMIC MECHANICAL PROPERTIES OF FUSED DEPOSITION MODELLING PROCESSED ULTEM MATERIAL

    OpenAIRE

    Adhiyamaan Arivazhagan; Ammar Saleem; S. H. Masood; Mostafa Nikzad; K. A. JAGADEESH

    2014-01-01

    Fused Deposition Modelling (FDM), a renowned Rapid Prototyping (RP) process, has been successfully implemented in several industries to fabricate concept models and prototypes for rapid manufacturing. This study furnishes terse notes about the material damping properties of FDM made ULTEM samples considering the effect of FDM process parameters. Dynamic Mechanical Analysis (DMA) is carried out using DMA 2980 equipment to study the dynamic response of the FDM material subjected to single canti...

  10. Modeling of atmospheric iron processing carried by mineral dust and its deposition to ocean

    Science.gov (United States)

    Nickovic, Slobodan; Vukovic, Ana; Vujadinovic, Mirjam

    2014-05-01

    Relatively insoluble iron in dust originating from desert soils increases its solubility after Fe carried by mineral dust is chemically processed by the atmosphere. After dust is deposited deposition to the ocean, soluble Fe as a nutrient could enhance the marine primary production. The atmospheric dust cycle is driven by the atmospheric processes often of smaller, meso-scales. The soil mineralogy of dust emitted from sources determines also how much Fe in the aerosol will be finding. Once Fe is exposed to the atmospheric processes, the atmospheric radiation, clouds and polluted air will chemically affect the iron in dust. Global dust-iron models, having typical horizontal resolutions of 100-300 km which are mostly used to numerically simulate the fate of iron in the atmosphere can provide rather global picture of the dust and iron transport, but not details. Such models often introduce simplistic approximation on the Fe content in dust-productive soils. To simulate the Fe processing we instead implemented a high resolution regional atmospheric dust-iron model with detailed 1km global map for the geographic distribution of Fe content in soil. We also introduced a parameterization of the Fe processing caused by dust mineralogy, cloud processes and solar radiation. We will present results from simulation experiments in order to explore the model capability to reproduce major observed patterns of deposited Fe into the Atlantic cruises.

  11. Atomic Layer Deposition to Enable the Production, Optimization and Protection of Spaceflight Hardware Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Atomic Layer Deposition (ALD) is a cost effective nano-manufacturing technique that allows for the conformal coating of substrates with atomic control in a benign...

  12. Atomic Layer Deposition to Enable the Production, Optimization and Protection of Spaceflight Hardware Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Atomic Layer Deposition (ALD) is a cost effective nano-manufacturing technique that allows for the conformal coating of substrates with atomic control in a benign...

  13. Structure and depositional processes of a gravelly tsunami deposit in a shallow marine setting: Lower Cretaceous Miyako Group, Japan

    Science.gov (United States)

    Fujino, S.; Masuda, F.; Tagomori, S.; Matsumoto, D.

    2006-06-01

    This study reports a newly discovered gravelly tsunami deposit from the Lower Cretaceous Miyako Group, Japan. The deposit was formed in an open shallow marine setting. The event deposit erosionally overlies shoreface deposits and shows marked lateral facies change. At the basin margin, the deposit is composed mainly of amalgamated HCS sandstones with liquefaction structures, overlain by finer sediments that contain many plant fragments or micas. Conglomerates accompanying the HCS sandstones contain molluscan fossils and many coral clasts. In the basin center, the event deposit is made up mainly of conglomerates and lenticular sandstone beds, and passes upwards into alternating sandstones and siltstones. A condensed organic debris layer is intercalated within the alternating section. Conglomerates contain abundant beach gravel, and also contain beachrock, coral blocks, and boulders. Bivalve fossils are well preserved despite their occurrence in grain-supported conglomerates. The event deposit is divided into sub-layers bounded by internal scours that are wavy and intersect. Each sub-layer consists of a conglomerate grading into a sandstone layer. Imbrications just above the scours in sub-layers show seawards paleocurrents; however, imbrications just beneath the sandstone horizons in the same sub-layers feature landward paleocurrents. Respective sub-layers in the tsunami deposit were formed by substrate erosion due to backwash flow, gravel deposition, reworking by flood flow, and sand deposition during the stagnant water period. The overall upward-fining trend reflects decline of the tsunami event. Development of the gravelly deposit in the central part of the basin and lateral facies change may be attributed to hydrodynamic response of the tsunami pulse to local bathymetry and geography.

  14. Numerical solution of moving boundary problem for deposition process in solid fuel gas generator

    Science.gov (United States)

    Volokhov, V. M.; Dorofeenko, S. O.; Sharov, M. S.; Toktaliev, P. D.

    2016-11-01

    Moving boundary problem in application to process of depositions formation in gas generator are considered. Gas generator, as a part of fuel preparation system of high-speed vehicle, convert solid fuel into multicomponent multiphase mixture, which further burned down in combustion chamber. Mathematical model of two-phase “gas-solid particles” flow, including Navier-Stokes equations for turbulent flow in gas generator and mass, impulse conservations laws for elementary depositions layer are proposed. Verification of proposed mathematical model for depositions mass in gas generator conditions is done. Further possible improvements of proposed model, based on more detail accounting of particle-wall interaction and wall's surface adhesion properties are analyzed.

  15. Effect of Processing Parameters on Performance of Spray-Deposited Organic Thin-Film Transistors

    Directory of Open Access Journals (Sweden)

    Jack W. Owen

    2011-01-01

    Full Text Available The performance of organic thin-film transistors (OTFTs is often strongly dependent on the fabrication procedure. In this study, we fabricate OTFTs of soluble small-molecule organic semiconductors by spray-deposition and explore the effect of processing parameters on film morphology and device mobility. In particular, we report on the effect of the nature of solvent, the pressure of the carrier gas used in deposition, and the spraying distance. We investigate the surface morphology using scanning force microscopy and show that the molecules pack along the π-stacking direction, which is the preferred charge transport direction. Our results demonstrate that we can tune the field-effect mobility of spray-deposited devices two orders of magnitude, from 10−3 cm2/Vs to 10−1 cm2/Vs, by controlling fabrication parameters.

  16. Purity and resistivity improvements for electron-beam-induced deposition of Pt

    Energy Technology Data Exchange (ETDEWEB)

    Mulders, J.J.L. [FEI Company, Eindhoven (Netherlands)

    2014-12-15

    Electron-beam-induced deposition (EBID) of platinum is used by many researchers. Its main application is the formation of a protective layer and the ''welding material'' for making a TEM lamella with a focused ion beam thinning process. For this application, the actual composition of the deposition is less relevant, and in practice, both the mechanical strength and the conductivity are sufficient. Another important application is the creation of an electrical connection to nanoscale structures such as nano-wires and graphene. To serve as an electrical contact, the resistivity of the Pt deposited structure has to be sufficiently low. Using the commonly used precursor MeCpPtMe{sub 3} for deposition, the resistivity as created by the basic process is 10{sup +5}-10{sup +6} higher than the value for bulk Pt, which is 10.6 μΩ cm. The reason for this is the high abundance of carbon in the deposition. To improve the deposition process, much attention has been given by the research community to parameter optimization, to ex situ or in situ removal of carbon by anneal steps, to prevention of carbon deposition by use of a carbon-free precursor, to electron beam irradiation under a high flux of oxygen and to the combination with other techniques such as atomic layer deposition (ALD). In the latter technique, the EBID structures are used as a 1-nm-thick seed layer only, while the ALD is used to selectively add pure Pt. These techniques have resulted in a low resistivity, today approaching the 10-150 μΩ cm, while the size and shape of the structure are preserved. Therefore, now, the technique is ready for application in the field of contacting nano-wires. (orig.)

  17. Magnetic and electrical characterization of nickel-rich NiFe thin films synthesized by atomic layer deposition and subsequent thermal reduction

    Science.gov (United States)

    Espejo, A. P.; Zierold, R.; Gooth, J.; Dendooven, J.; Detavernier, C.; Escrig, J.; Nielsch, K.

    2016-08-01

    Nickel-rich NiFe thin films (Ni92Fe8, Ni89Fe11 and Ni83Fe17) were prepared by combining atomic layer deposition (ALD) with a subsequent thermal reduction process. In order to obtain Ni x Fe1-x O y films, one ALD supercycle was performed according to the following sequence: m NiCp2/O3, with m = 1, 2 or 3, followed by one FeCp2/O3 cycle. The supercycle was repeated n times. The thermal reduction process in hydrogen atmosphere was investigated by in situ x-ray diffraction studies as a function of temperature. The metallic nickel iron alloy thin films were investigated and characterized with respect to crystallinity, morphology, resistivity, and magnetism. As proof-of-concept magnetic properties of an array of Ni83Fe17, close to the perfect Permalloy stoichiometry, nanotubes and an isolated tube were investigated.

  18. Plasma polymers deposited in atmospheric pressure dielectric barrier discharges: Influence of process parameters on film properties

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Katja, E-mail: k.fricke@inp-greifswald.de [Leibniz Institute for Plasma Science and Technology e.V. (INP Greifswald), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Girard-Lauriault, Pierre-Luc [Plasma Processing Laboratory, Department of Chemical Engineering, McGill University, 3610 rue University, Montreal, QC H3A 0C5 (Canada); Weltmann, Klaus-Dieter [Leibniz Institute for Plasma Science and Technology e.V. (INP Greifswald), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Wertheimer, Michael R. [Department of Engineering Physics, École Polytechnique de Montréal, Box 6079, Station Centre-Ville, Montreal, QC H3C 3A7 (Canada)

    2016-03-31

    We present results on the deposition of plasma polymer (PP) films in a dielectric barrier discharge system fed with mixtures of argon or nitrogen carrier gas plus different hydrocarbon precursors, where the latter possess different carbon-to-hydrogen ratios: CH{sub 4} < C{sub 2}H{sub 6} < C{sub 2}H{sub 4} = C{sub 3}H{sub 6} < C{sub 2}H{sub 2}. The influence of precursor gas mixture and flow rate, excitation frequency, and absorbed power on PP film compositions and properties has been investigated. The discharge was characterized by electrical measurements, while the chemical compositions and structures of coatings were analysed by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, total combustion, and elastic recoil detection analyses, the latter two for determining carbon-to-hydrogen ratios. Scanning electron microscopy was used to study the coatings' morphology, and profilometry for evaluating deposition rates. - Highlights: • Atmospheric pressure DBD is used to deposit organic hydrocarbon films. • High deposition rates can be achieved by varying the power and/or gas mixture ratio. • Process parameters affect the films' surface chemical composition and morphology. • Deposited films are not soluble in aqueous environment. • No delamination of coatings produced from argon plasma.

  19. Low-temperature roll-to-roll atmospheric atomic layer deposition of Al₂O₃ thin films.

    Science.gov (United States)

    Ali, Kamran; Choi, Kyung-Hyun

    2014-12-02

    The Al2O3 thin films deposition through conventional ALD systems is a well-established process. The process under low temperatures has been studied by few research groups. In this paper, we report on the detailed study of low-temperature Al2O3 thin films deposited via a unique in-house built system of roll-to-roll atmospheric atomic layer deposition (R2R-AALD) using a multiple-slit gas source head. Al2O3 thin films have been grown on polyethylene terephthalate substrates under a very low-temperature zone of room temperature to 50 °C and working pressure of 750 Torr, which is very near to atmospheric pressure (760 Torr). Al2O3 thin films with superior properties were achieved in the temperature range of the ALD window. An appreciable growth rate of 0.97 Å/cycle was observed for the films deposited at 40 °C. The films have good morphological features with a very low average arithmetic roughness (Ra) of 0.90 nm. The films also showed good chemical, electrical, and optical characteristics. It was observed that the film characteristics improve with the increase in deposition temperature to the range of the ALD window. The fabrication of Al2O3 films was confirmed by X-ray photoelectron spectroscopy (XPS) analysis with the appearance of Al 2p, Al 2s, and O 1s peaks at the binding energies of 74, 119, and 531 eV, respectively. The chemical composition was also supported by the Fourier transform infrared spectroscopy (FTIR). The fabricated Al2O3 films demonstrate good insulating properties and optical transmittance of more than 85% in the visible region. The results state that Al2O3 thin films can be effectively fabricated through the R2R-AALD system at temperatures as low as 40 °C.

  20. Surface chemistry for molecular layer deposition of organic and hybrid organic-inorganic polymers.

    Science.gov (United States)

    George, Steven M; Yoon, Byunghoon; Dameron, Arrelaine A

    2009-04-21

    The fabrication of many devices in modern technology requires techniques for growing thin films. As devices miniaturize, manufacturers will need to control thin film growth at the atomic level. Because many devices have challenging morphologies, thin films must be able to coat conformally on structures with high aspect ratios. Techniques based on atomic layer deposition (ALD), a special type of chemical vapor deposition, allow for the growth of ultra-thin and conformal films of inorganic materials using sequential, self-limiting reactions. Molecular layer deposition (MLD) methods extend this strategy to include organic and hybrid organic-inorganic polymeric materials. In this Account, we provide an overview of the surface chemistry for the MLD of organic and hybrid organic-inorganic polymers and examine a variety of surface chemistry strategies for growing polymer thin films. Previously, surface chemistry for the MLD of organic polymers such as polyamides and polyimides has used two-step AB reaction cycles using homo-bifunctional reactants. However, these reagents can react twice and eliminate active sites on the growing polymer surface. To avoid this problem, we can employ alternative precursors for MLD based on hetero-bifunctional reactants and ring-opening reactions. We can also use surface activation or protected chemical functional groups. In addition, we can combine the reactants for ALD and MLD to grow hybrid organic-inorganic polymers that should display interesting properties. For example, using trimethylaluminum (TMA) and various diols as reactants, we can achieve the MLD of alucone organic-inorganic polymers. We can alter the chemical and physical properties of these organic-inorganic polymers by varying the organic constituent in the diol or blending the alucone MLD films with purely inorganic ALD films to build a nanocomposite or nanolaminate. The combination of ALD and MLD reactants enlarges the number of possible sequential self-limiting surface

  1. Growth process conditions of tungsten oxide thin films using hot-wire chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Houweling, Z. Silvester, E-mail: Z.S.Houweling@uu.nl [Nanophotonics - Physics of Devices, Debye Institute for Nanomaterials Science, Utrecht University, Princetonlaan 4, 3584 CB Utrecht (Netherlands); Geus, John W. [Electron Microscopy, Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands); Jong, Michiel de; Harks, Peter-Paul R.M.L.; Werf, Karine H.M. van der; Schropp, Ruud E.I. [Nanophotonics - Physics of Devices, Debye Institute for Nanomaterials Science, Utrecht University, Princetonlaan 4, 3584 CB Utrecht (Netherlands)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Process parameters to control hot-wire CVD of WO{sub 3-x} are categorized. Black-Right-Pointing-Pointer Growth time, oxygen partial pressure, filament and substrate temperature are varied. Black-Right-Pointing-Pointer Chemical and crystal structure, optical bandgap and morphology are determined. Black-Right-Pointing-Pointer Oxygen partial pressure determines the deposition rate up to as high as 36 {mu}m min{sup -1}. Black-Right-Pointing-Pointer Nanostructures, viz. wires, crystallites and closed crystallite films, are controllably deposited. - Abstract: We report the growth conditions of nanostructured tungsten oxide (WO{sub 3-x}) thin films using hot-wire chemical vapor deposition (HWCVD). Two tungsten filaments were resistively heated to various temperatures and exposed to an air flow at various subatmospheric pressures. The oxygen partial pressure was varied from 6.0 Multiplication-Sign 10{sup -6} to 1.0 mbar and the current through the filaments was varied from 4.0 to 9.0 A, which constitutes a filament temperature of 1390-2340 Degree-Sign C in vacuum. It is observed that the deposition rate of the films is predominantly determined by the oxygen partial pressure; it changes from about 1 to about 36,000 nm min{sup -1} in the investigated range. Regardless of the oxygen partial pressure and filament temperature used, thin films with a nanogranular morphology are obtained, provided that the depositions last for 30 min or shorter. The films consist either of amorphous or partially crystallized WO{sub 3-x} with high averaged transparencies of over 70% and an indirect optical band gap of 3.3 {+-} 0.1 eV. A prolonged deposition time entails an extended exposure of the films to thermal radiation from the filaments, which causes crystallization to monoclinic WO{sub 3} with diffraction maxima due to the (0 0 2), (2 0 0) and (0 2 0) crystallographic planes, furthermore the nanograins sinter and the films exhibit a cone

  2. Processes and environmental significance of the subglacial chemical deposits in Tianshan Mountains

    Institute of Scientific and Technical Information of China (English)

    LIU; Gengnian; LUO; Risheng; CAO; Jun

    2005-01-01

    On the bedrock surface of Glacier No.1 in the headwater of Urumqi River, Tianshan Mts., well layered and crystallized subglacial calcite precipitations were discovered. Based on observations and analysis of the surface form, sedimentary texture and structure, and chemical composition of the deposits, clues about the subglacial processes and environment are deduced. The radial-growth crustation texture of the deposits, which builds up in the saturated CaCO3 solution, proves the existence of pressure melting water and water films under Glacier No.1; and their rhythmic beddings, dissolved planes and unconformable contacts show that the water films responsible for the formation of these structures were in a wide range of spatial as well as temporal variations. Though formed under continental glacier in non-limestone area, the deposits are quite similar to those formed under temperate glaciers in limestone areas, a fact that shows a similar process of chemical precipitation between the two. Hence the enrichment of calcium in the subglacial melting water and the process of precipitation have actually little to do with the bedrock lithology and the glacier types. The cemented detritus in the deposits are rich in Fe and Al while depleted in K, Na and Si; also the included clay mineral consists mainly of illite, which reveals some weak chemical weathering under the continental glacier. The subglacial CaCO3 precipitates when plenty of Ca++ melt into the subglacial melting water on a comparatively enclosed ice-bedrock interface under a high CO2 partial pressure, the forming of subglacial chemical deposits therefore offers unequivocal evidence for the ongoing of subglacial chemical reactions.

  3. Chemical resistance of thin film materials based on metal oxides grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sammelselg, Väino, E-mail: vaino.sammelselg@ut.ee [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia); Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu (Estonia); Netšipailo, Ivan; Aidla, Aleks; Tarre, Aivar; Aarik, Lauri; Asari, Jelena; Ritslaid, Peeter; Aarik, Jaan [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia)

    2013-09-02

    Etching rate of technologically important metal oxide thin films in hot sulphuric acid was investigated. The films of Al-, Ti-, Cr-, and Ta-oxides studied were grown by atomic layer deposition (ALD) method on silicon substrates from different precursors in large ranges of growth temperatures (80–900 °C) in order to reveal process parameters that allow deposition of coatings with higher chemical resistance. The results obtained demonstrate that application of processes that yield films with lower concentration of residual impurities as well as crystallization of films in thermal ALD processes leads to significant decrease of etching rate. Crystalline films of materials studied showed etching rates down to values of < 5 pm/s. - Highlights: • Etching of atomic layer deposited thin metal oxide films in hot H{sub 2}SO{sub 4} was studied. • Smallest etching rates of < 5 pm/s for TiO{sub 2}, Al{sub 2}O{sub 3}, and Cr{sub 2}O{sub 3} were reached. • Highest etching rate of 2.8 nm/s for Al{sub 2}O{sub 3} was occurred. • Remarkable differences in etching of non- and crystalline films were observed.

  4. Properties of multilayer gallium and aluminum doped ZnO(GZO/AZO)transparent thin films deposited by pulsed laser deposition process

    Institute of Scientific and Technical Information of China (English)

    Jin-Hyum SHIN; Dong-Kyun SHIN; Hee-Young LEE; Jai-Yeoul LEE

    2011-01-01

    Multilayer gallium and aluminum doped ZnO (GZO/AZO) films were fabricated by alternative deposition of Ga-doped zinc oxide(GZO) and Al-doped zinc oxide(AZO) thin film by using pulsed laser deposition(PLD) process. The electrical and optical properties of these GZO/AZO thin films were investigated and compared with those of GZO and AZO thin films. The GZO/AZO GZO/AZO thin films linearly decreases with increasing the Al ratio.

  5. Ionic properties of ultrathin yttria-stabilized zirconia thin films fabricated by atomic layer deposition with water, oxygen, and ozone

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Keun; Jang, Dong Young; Kim, Jun Woo [School of Mechanical Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of); Bae, Kiho [School of Mechanical Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of); High-Temperature Energy Materials Research Center, Korea Institute of Science and Technology (KIST), Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Shim, Joon Hyung, E-mail: shimm@korea.ac.kr [School of Mechanical Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713 (Korea, Republic of)

    2015-08-31

    We compared the ionic properties of yttria-stabilized zirconia (YSZ) thin films prepared by atomic layer deposition (ALD) using various oxidants including water, oxygen, and ozone. Cross-plane conductivity measurements were performed at low temperature (50 °C) and high temperature (450 °C) using AC impedance spectroscopy. As a result, we have confirmed that the conductivity of ALD YSZ films below 300 °C is greater by several orders of magnitude compared to the nano-scale YSZ thin films synthesized by other conventional techniques. Among the ALD YSZ samples, ALD YSZ fabricated using water showed the highest conductivity while ALD YSZ fabricated using ozone showed the lowest. We have analyzed this result in relation with grain morphology characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM), and the chemical binding states measured by X-ray photoelectron spectroscopy (XPS). - Highlights: • YSZ is prepared by atomic layer deposition (ALD) with H{sub 2}O, O{sub 2}, and O{sub 3} as oxidants. • Grain size of ALD YSZ membranes deposited using H{sub 2}O is the smallest. • Conductivity of ALD YSZ made with H{sub 2}O shows the highest value below 300 °C. • Conductivity trends coincide with the hydroxyl group content measured by XPS.

  6. Multi-Directional Growth of Aligned Carbon Nanotubes Over Catalyst Film Prepared by Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Zhou Kai

    2010-01-01

    Full Text Available Abstract The structure of vertically aligned carbon nanotubes (CNTs severely depends on the properties of pre-prepared catalyst films. Aiming for the preparation of precisely controlled catalyst film, atomic layer deposition (ALD was employed to deposit uniform Fe2O3 film for the growth of CNT arrays on planar substrate surfaces as well as the curved ones. Iron acetylacetonate and ozone were introduced into the reactor alternately as precursors to realize the formation of catalyst films. By varying the deposition cycles, uniform and smooth Fe2O3 catalyst films with different thicknesses were obtained on Si/SiO2 substrate, which supported the growth of highly oriented few-walled CNT arrays. Utilizing the advantage of ALD process in coating non-planar surfaces, uniform catalyst films can also be successfully deposited onto quartz fibers. Aligned few-walled CNTs can be grafted on the quartz fibers, and they self-organized into a leaf-shaped structure due to the curved surface morphology. The growth of aligned CNTs on non-planar surfaces holds promise in constructing hierarchical CNT architectures in future.

  7. Conformal SiO2 coating of sub-100 nm diameter channels of polycarbonate etched ion-track channels by atomic layer deposition

    Directory of Open Access Journals (Sweden)

    Nicolas Sobel

    2015-02-01

    Full Text Available Polycarbonate etched ion-track membranes with about 30 µm long and 50 nm wide cylindrical channels were conformally coated with SiO2 by atomic layer deposition (ALD. The process was performed at 50 °C to avoid thermal damage to the polymer membrane. Analysis of the coated membranes by small angle X-ray scattering (SAXS reveals a homogeneous, conformal layer of SiO2 in the channels at a deposition rate of 1.7–1.8 Å per ALD cycle. Characterization by infrared and X-ray photoelectron spectroscopy (XPS confirms the stoichiometric composition of the SiO2 films. Detailed XPS analysis reveals that the mechanism of SiO2 formation is based on subsurface crystal growth. By dissolving the polymer, the silica nanotubes are released from the ion-track membrane. The thickness of the tube wall is well controlled by the ALD process. Because the track-etched channels exhibited diameters in the range of nanometres and lengths in the range of micrometres, cylindrical tubes with an aspect ratio as large as 3000 have been produced.

  8. Conformal SiO2 coating of sub-100 nm diameter channels of polycarbonate etched ion-track channels by atomic layer deposition.

    Science.gov (United States)

    Sobel, Nicolas; Hess, Christian; Lukas, Manuela; Spende, Anne; Stühn, Bernd; Toimil-Molares, M E; Trautmann, Christina

    2015-01-01

    Polycarbonate etched ion-track membranes with about 30 µm long and 50 nm wide cylindrical channels were conformally coated with SiO2 by atomic layer deposition (ALD). The process was performed at 50 °C to avoid thermal damage to the polymer membrane. Analysis of the coated membranes by small angle X-ray scattering (SAXS) reveals a homogeneous, conformal layer of SiO2 in the channels at a deposition rate of 1.7-1.8 Å per ALD cycle. Characterization by infrared and X-ray photoelectron spectroscopy (XPS) confirms the stoichiometric composition of the SiO2 films. Detailed XPS analysis reveals that the mechanism of SiO2 formation is based on subsurface crystal growth. By dissolving the polymer, the silica nanotubes are released from the ion-track membrane. The thickness of the tube wall is well controlled by the ALD process. Because the track-etched channels exhibited diameters in the range of nanometres and lengths in the range of micrometres, cylindrical tubes with an aspect ratio as large as 3000 have been produced.

  9. INFLUENCE OF PROCESS PARAMETERS ON DIMENSIONAL ACCURACY OF PARTS MANUFACTURED USING FUSED DEPOSITION MODELLING TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Filip Górski

    2013-09-01

    Full Text Available The paper presents the results of experimental study – part of research of additive technology using thermoplastics as a build material, namely Fused Deposition Modelling (FDM. Aim of the study was to identify the relation between basic parameter of the FDM process – model orientation during manufacturing – and a dimensional accuracy and repeatability of obtained products. A set of samples was prepared – they were manufactured with variable process parameters and they were measured using 3D scanner. Significant differences in accuracy of products of the same geometry, but manufactured with different set of process parameters were observed.

  10. A new highly automated sputter equipment for in situ investigation of deposition processes with synchrotron radiation

    Science.gov (United States)

    Döhrmann, Ralph; Botta, Stephan; Buffet, Adeline; Santoro, Gonzalo; Schlage, Kai; Schwartzkopf, Matthias; Bommel, Sebastian; Risch, Johannes F. H.; Mannweiler, Roman; Brunner, Simon; Metwalli, Ezzeldin; Müller-Buschbaum, Peter; Roth, Stephan V.

    2013-04-01

    HASE (Highly Automated Sputter Equipment) is a new mobile setup developed to investigate deposition processes with synchrotron radiation. HASE is based on an ultra-high vacuum sputter deposition chamber equipped with an in-vacuum sample pick-and-place robot. This enables a fast and reliable sample change without breaking the vacuum conditions and helps to save valuable measurement time, which is required for experiments at synchrotron sources like PETRA III at DESY. An advantageous arrangement of several sputter guns, mounted on a rotative flange, gives the possibility to sputter under different deposition angles or to sputter different materials on the same substrate. The chamber is also equipped with a modular sample stage, which allows for the integration of different sample environments, such as a sample heating and cooling device. The design of HASE is unique in the flexibility. The combination of several different sputtering methods like standard deposition, glancing angle deposition, and high pressure sputter deposition combined with heating and cooling possibil-ities of the sample, the large exit windows, and the degree of automation facilitate many different grazing incidence X-ray scattering experiments, such as grazing incidence small and wide angle X-ray scattering, in one setup. In this paper we describe in detail the design and the performance of the new equipment and present the installation of the HASE apparatus at the Micro and Nano focus X-ray Scattering beamline (MiNaXS) at PETRA III. Furthermore, we describe the measurement options and present some selected results. The HASE setup has been successfully commissioned and is now available for users.

  11. A new highly automated sputter equipment for in situ investigation of deposition processes with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Doehrmann, Ralph; Botta, Stephan; Buffet, Adeline; Santoro, Gonzalo; Schlage, Kai; Schwartzkopf, Matthias; Risch, Johannes F. H.; Mannweiler, Roman; Roth, Stephan V. [DESY, Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg (Germany); Bommel, Sebastian [DESY, Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22607 Hamburg (Germany); Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstr. 15, D-12489 Berlin (Germany); Brunner, Simon; Metwalli, Ezzeldin; Mueller-Buschbaum, Peter [Lehrstuhl fuer Funktionelle Materialien, Physik-Department, Technische Universitaet Muenchen, James-Franck-Str. 1, D-85748 Garching (Germany)

    2013-04-15

    HASE (Highly Automated Sputter Equipment) is a new mobile setup developed to investigate deposition processes with synchrotron radiation. HASE is based on an ultra-high vacuum sputter deposition chamber equipped with an in-vacuum sample pick-and-place robot. This enables a fast and reliable sample change without breaking the vacuum conditions and helps to save valuable measurement time, which is required for experiments at synchrotron sources like PETRA III at DESY. An advantageous arrangement of several sputter guns, mounted on a rotative flange, gives the possibility to sputter under different deposition angles or to sputter different materials on the same substrate. The chamber is also equipped with a modular sample stage, which allows for the integration of different sample environments, such as a sample heating and cooling device. The design of HASE is unique in the flexibility. The combination of several different sputtering methods like standard deposition, glancing angle deposition, and high pressure sputter deposition combined with heating and cooling possibil-ities of the sample, the large exit windows, and the degree of automation facilitate many different grazing incidence X-ray scattering experiments, such as grazing incidence small and wide angle X-ray scattering, in one setup. In this paper we describe in detail the design and the performance of the new equipment and present the installation of the HASE apparatus at the Micro and Nano focus X-ray Scattering beamline (MiNaXS) at PETRA III. Furthermore, we describe the measurement options and present some selected results. The HASE setup has been successfully commissioned and is now available for users.

  12. Effects of Processing Variables on Tantalum Nitride by Reactive-Ion-Assisted Magnetron Sputtering Deposition

    Science.gov (United States)

    Wei, Chao‑Tsang; Shieh, Han‑Ping D.

    2006-08-01

    The binary compound tantalum nitride (TaN) and ternary compounds tantalum tungsten nitrides (Ta1-xWxNy) exhibit interesting properties such as high melting point, high hardness, and chemical inertness. Such nitrides were deposited on a tungsten carbide (WC) die and silicon wafers by ion-beam-sputter evaporation of the respective metal under nitrogen ion-assisted deposition (IAD). The effects of N2/Ar flux ratio, post annealing, ion-assisted deposition, deposition rate, and W doping in coating processing variables on hardness, load critical scratching, oxidation resistance, stress and surface roughness were investigated. The optimum N2/Ar flux ratios in view of the hardness and critical load of TaN and Ta1-xWxNy films were ranged from 0.9 to 1.0. Doping W into TaN to form Ta1-xWxNy films led significant increases in hardness, critical load, oxidation resistance, and reduced surface roughness. The optimum doping ratio was [W/(W+Ta)]=0.85. From the deposition rate and IAD experiments, the stress in the films is mainly contributed by sputtering atoms. The lower deposition rate at a high N2/Ar flux ratio resulted in a higher compressive stress. A high compressive residual stress accounts for a high hardness. The relatively high compressive stress was attributed primarily to peening by atoms, ions and electrons during film growth, the Ta1-xWxNy films showed excellent hardness and strength against a high temperature, and sticking phenomena can essentially be avoided through their use. Ta1-xWxNy films showed better performance than the TaN film in terms of mechanical properties and oxidation resistance.

  13. Ore Zoning and Dynamics of Ore—Forming Processes of Yinshan Polymetallic Deposit in Dexing,Jiangxi

    Institute of Scientific and Technical Information of China (English)

    张德会; 於崇文; 等

    1997-01-01

    The Yinshan deposit,one of the large-scale Cu-Pb-Zn-Au-Ag polymetallic deposits,may be named a middle-low temperature subvolcanic hydrothermal deposit and referred to as the "transitional deposit"linking mineralization of the epithermal and porphyry coppertypes.In this paper,the characteristics and structures of ore zoning are briefly described.On the basis of the dynamics of ore-forming processes and applying computer numerical simulation technique,the mechanism of ore zoning is discussed and a concealed igneous body controlling ore deposition at depth of the Yinshan mine is predicted.

  14. Deposition of TiO2/Al2O3 bilayer on hydrogenated diamond for electronic devices: Capacitors, field-effect transistors, and logic inverters

    Science.gov (United States)

    Liu, J. W.; Liao, M. Y.; Imura, M.; Banal, R. G.; Koide, Y.

    2017-06-01

    The wide bandgap semiconductor diamond has been studied to develop high-power and high-frequency electronic devices. Here, high dielectric constant (high-k) TiO2/Al2O3 bilayers are deposited on hydrogenated diamond (H-diamond) channel layers using sputter deposition (SD) and atomic layer deposition (ALD) techniques. Thin ALD-Al2O3 films are employed as buffer layers for the SD-TiO2 and ALD-TiO2 on H-diamond to suppress plasma discharge effect and to decrease leakage current density (J), respectively. The electrical properties of the resulting TiO2/Al2O3/H-diamond metal-oxide-semiconductor (MOS) capacitors, MOS field-effect transistors (MOSFETs), and MOSFET logic inverters are investigated. With the same thickness (4.0 nm) for ALD-Al2O3 buffer layer, the ALD-TiO2/ALD-Al2O3/H-diamond MOS capacitor shows a lower J and better capacitance-voltage characteristics than the SD-TiO2/ALD-Al2O3/H-diamond capacitor. The maximum capacitance of the ALD-TiO2/ALD-Al2O3/H-diamond capacitor and the k value of the ALD-TiO2/ALD-Al2O3 bilayer are 0.83 μF cm-2 and 27.2, respectively. Valence band offset between ALD-TiO2 and H-diamond is calculated to be 2.3 ± 0.2 eV based on the element binding energies measured using an X-ray photoelectron spectroscopy technique. Both the SD-TiO2/ALD-Al2O3/H-diamond and ALD-TiO2/ALD-Al2O3/H-diamond MOSFETs show p-type, pinch-off, and enhancement mode characteristics with on/off current ratios around 109. The subthreshold swings of them are 115 and as low as 79 mV dec-1, respectively. The ALD-TiO2/ALD-Al2O3/H-diamond MOSFET logic inverters, when coupled with load resistors, show distinct inversion characteristics with gains of 6.2-12.7.

  15. An Experimental Study on Slurry Erosion Resistance of Single and Multilayered Deposits of Ni-WC Produced by Laser-Based Powder Deposition Process

    Science.gov (United States)

    Balu, Prabu; Hamid, Syed; Kovacevic, Radovan

    2013-11-01

    Single and multilayered deposits containing different mass fractions of tungsten carbide (WC) in nickel (Ni)-matrix (NT-20, NT-60, NT-80) are deposited on a AISI 4140 steel substrate using a laser-based powder deposition process. The transverse cross section of the coupons reveals that the higher the mass fraction of WC in Ni-matrix leads to a more uniform distribution through Ni-matrix. The slurry erosion resistance of the fabricated coupons is tested at three different impingement angles using an abrasive water jet cutting machine, which is quantified based on the erosion rate. The top layer of a multilayered deposit (i.e., NT-60 in a two-layer NT-60 over NT-20 deposit) exhibits better erosion resistance at all three tested impingement angles when compared to a single-layer (NT-60) deposit. A definite increase in the erosion resistance is noted with an addition of nano-size WC particles. The relationship between the different mass fractions of reinforcement (WC) in the deposited composite material (Ni-WC) and their corresponding matrix (Ni) hardness on the erosion rate is studied. The eroded surface is analyzed in the light of a three-dimensional (3-D) profilometer and a scanning electron microscope (SEM). The results show that a volume fraction of approximately 62% of WC with a Ni-matrix hardness of 540 HV resulting in the gouging out of WC from the Ni-matrix by the action of slurry. It is concluded that the slurry erosion resistance of the AISI 4140 steel can be significantly enhanced by introducing single and multilayered deposits of Ni-WC composite material fabricated by the laser-based powder deposition process.

  16. THE ROLE OF CRYOGENIC PROCESSES IN THE FORMATION OF LOESS DEPOSITS

    Directory of Open Access Journals (Sweden)

    Vyacheslav N. Konishchev

    2015-01-01

    Full Text Available The paper describes a new approach to the analysis of the genetic nature of mineral substances in loess deposits. In permafrost under the influence of multiple alternate freezing and thawing in dispersed deposits, quartz particles accumulate the 0.05-0.01 mm fraction, while feldspars are crushed to a coarse fraction of 0.1-0.05 mm. In dispersed sediments formed in temperate and warm climatic zones, the granulometric spectrum of quartz and feldspar has the opposite pattern. The proposed methodology is based on a differential analysis of the distribution of these minerals by the granulometric spectrum. We have proposed two criteria - the coefficient of cryogenic contrast (CCC and the coefficient of distribution of heavy minerals, which allow determination of the degree of participation of cryogenic processes in the formation of loess sediments and processes of aeolian or water sedimentation.

  17. Effects of O2 plasma post-treatment on ZnO: Ga thin films grown by H2O-thermal ALD

    Science.gov (United States)

    Lee, Yueh-Lin; Chuang, Jia-Hao; Huang, Tzu-Hsuan; Ho, Chong-Long; Wu, Meng-Chyi

    2013-03-01

    Transparent conducting oxides have been widely employed in optoelectronic devices using the various deposition methods such as sputtering, thermal evaporator, and e-gun evaporator technologies.1-3 In this work, gallium doped zinc oxide (ZnO:Ga) thin films were grown on glass substrates via H2O-thermal atomic layer deposition (ALD) at different deposition temperatures. ALD-GZO thin films were constituted as a layer-by-layer structure by stacking zinc oxides and gallium oxides. Diethylzinc (DEZ), triethylgallium (TEG) and H2O were used as zinc, gallium precursors and oxygen source, respectively. Furthermore, we investigated the influences of O2 plasma post-treatment power on the surface morphology, electrical and optical property of ZnO:Ga films. As the result of O2 plasma post-treatment, the characteristics of ZnO:Ga films exhibit a smooth surface, low resistivity, high carrier concentration, and high optical transmittance in the visible spectrum. However, the transmittance decreases with O2 plasma power in the near- and mid-infrared regions.

  18. On adsorption of aluminium and methyl groups on silica for TMA/H2O process in atomic layer deposition of aluminium oxide nano layers

    Indian Academy of Sciences (India)

    Anu Philip; K Rajeev Kumar

    2010-04-01

    A detailed chemisorption mechanism is proposed for the atomic layer deposition (ALD) of aluminium oxide nano layers using trimethyl aluminum (TMA) and water as precursors. Six possible chemisorption mechanisms, complete ligand exchange, partial ligand exchange, simple dissociation, complete dissociation via ligand exchange, complete dissociation and association, are proposed and related parameters like ligand to metal ratio (L/M), concentrations of metal atoms and methyl groups adsorbed are calculated and compared against reported values. The maximum number of methyl groups that can get attached on the surface is calculated in a different way which yields a more realistic value of 6.25 per nm2 substrate area. The dependence of the number of metal atoms adsorbed on OH concentration is explained clearly. It is proposed that a combination of complete ligand exchange and complete dissociation is the most probable chemisorption mechanism taking place at various OH concentrations.

  19. Engineering the mechanical properties of ultrabarrier films grown by atomic layer deposition for the encapsulation of printed electronics

    Energy Technology Data Exchange (ETDEWEB)

    Bulusu, A.; Singh, A.; Kim, H. [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Wang, C. Y.; Dindar, A.; Fuentes-Hernandez, C.; Kippelen, B. [School of Electrical and Computer Engineering, Georgia Institute of Technology, and Center for Organic Photonics and Electronics, Atlanta, Georgia 30332 (United States); Cullen, D. [Oak Ridge National Laboratory, P.O. Box 2008 MS-6064, Oak Ridge, Tennessee 37831 (United States); Graham, S., E-mail: sgraham@gatech.edu [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Oak Ridge National Laboratory, P.O. Box 2008 MS-6064, Oak Ridge, Tennessee 37831 (United States)

    2015-08-28

    Direct deposition of barrier films by atomic layer deposition (ALD) onto printed electronics presents a promising method for packaging devices. Films made by ALD have been shown to possess desired ultrabarrier properties, but face challenges when directly grown onto surfaces with varying composition and topography. Challenges include differing nucleation and growth rates across the surface, stress concentrations from topography and coefficient of thermal expansion mismatch, elastic constant mismatch, and particle contamination that may impact the performance of the ALD barrier. In such cases, a polymer smoothing layer may be needed to coat the surface prior to ALD barrier film deposition. We present the impact of architecture on the performance of aluminum oxide (Al{sub 2}O{sub 3})/hafnium oxide (HfO{sub 2}) ALD nanolaminate barrier films deposited on fluorinated polymer layer using an optical calcium (Ca) test under damp heat. It is found that with increasing polymer thickness, the barrier films with residual tensile stress are prone to cracking resulting in rapid failure of the Ca sensor at 50 °C/85% relative humidity. Inserting a SiN{sub x} layer with residual compressive stress between the polymer and ALD layers is found to prevent cracking over a range of polymer thicknesses with more than 95% of the Ca sensor remaining after 500 h of testing. These results suggest that controlling mechanical properties and film architecture play an important role in the performance of direct deposited ALD barriers.

  20. Engineering the mechanical properties of ultrabarrier films grown by atomic layer deposition for the encapsulation of printed electronics

    Science.gov (United States)

    Bulusu, A.; Singh, A.; Wang, C. Y.; Dindar, A.; Fuentes-Hernandez, C.; Kim, H.; Cullen, D.; Kippelen, B.; Graham, S.

    2015-08-01

    Direct deposition of barrier films by atomic layer deposition (ALD) onto printed electronics presents a promising method for packaging devices. Films made by ALD have been shown to possess desired ultrabarrier properties, but face challenges when directly grown onto surfaces with varying composition and topography. Challenges include differing nucleation and growth rates across the surface, stress concentrations from topography and coefficient of thermal expansion mismatch, elastic constant mismatch, and particle contamination that may impact the performance of the ALD barrier. In such cases, a polymer smoothing layer may be needed to coat the surface prior to ALD barrier film deposition. We present the impact of architecture on the performance of aluminum oxide (Al2O3)/hafnium oxide (HfO2) ALD nanolaminate barrier films deposited on fluorinated polymer layer using an optical calcium (Ca) test under damp heat. It is found that with increasing polymer thickness, the barrier films with residual tensile stress are prone to cracking resulting in rapid failure of the Ca sensor at 50 °C/85% relative humidity. Inserting a SiNx layer with residual compressive stress between the polymer and ALD layers is found to prevent cracking over a range of polymer thicknesses with more than 95% of the Ca sensor remaining after 500 h of testing. These results suggest that controlling mechanical properties and film architecture play an important role in the performance of direct deposited ALD barriers.

  1. Pt-Ti/ALD-Al2O3/p-Si MOS Capacitors for Future ULSI Technology

    Directory of Open Access Journals (Sweden)

    Ashok M. Mahajan

    2011-01-01

    Full Text Available The high dielectric constant (high-k thin film of Al2O3 was deposited by using Plasma enhanced atomic layer deposition (PE-ALD technique. The electron beam evaporation system was used to deposit the Pt-Ti metal to fabricate the Pt-Ti/Al2O3/Si MOS capacitors. Thickness measurement of Al2O3 gate dielectric was carried out with variable angle spectroscopic ellipsometry, which is measured to be 2.83 nm. The MOS capacitors were characterized to evaluate the electrical properties using capacitance voltage (C-V analyzer at different measurement frequencies. Capacitance voltage measurement shows that, dielectric constant k ranges from 7.87 to 10.44. In CV curve a slight negative shift is observed in the flatband voltage because of presence of trap charges in the Al2O3 MOS capacitor. A lower equivalent oxide thickness (EOT of 1.057 nm is obtained for the fabricated Pt-Ti/ Al2O3 /Si MOS capacitors.

  2. Application of Thin ZnO ALD Layers in Fiber-Optic Fabry-Pérot Sensing Interferometers.

    Science.gov (United States)

    Majchrowicz, Daria; Hirsch, Marzena; Wierzba, Paweł; Bechelany, Michael; Viter, Roman; Jędrzejewska-Szczerska, Małgorzata

    2016-03-22

    In this paper we investigated the response of a fiber-optic Fabry-Pérot sensing interferometer with thin ZnO layers deposited on the end faces of the optical fibers forming the cavity. Standard telecommunication single-mode optical fiber (SMF-28) segments were used with the thin ZnO layers deposited by Atomic Layer Deposition (ALD). Measurements were performed with the interferometer illuminated by two broadband sources operating at 1300 nm and 1550 nm. Reflected interference signal was acquired by an optical spectrum analyzer while the length of the air cavity was varied. Thickness of the ZnO layers used in the experiments was 50 nm, 100 nm, and 200 nm. Uncoated SMF-28 fiber was also used as a reference. Based on the results of measurements, the thickness of the ZnO layers and the length of the cavity were selected in order to achieve good visibility. Following, the interferometer was used to determine the refractive index of selected liquids.

  3. Application of Thin ZnO ALD Layers in Fiber-Optic Fabry-Pérot Sensing Interferometers

    Directory of Open Access Journals (Sweden)

    Daria Majchrowicz

    2016-03-01

    Full Text Available In this paper we investigated the response of a fiber-optic Fabry-Pérot sensing interferometer with thin ZnO layers deposited on the end faces of the optical fibers forming the cavity. Standard telecommunication single-mode optical fiber (SMF-28 segments were used with the thin ZnO layers deposited by Atomic Layer Deposition (ALD. Measurements were performed with the interferometer illuminated by two broadband sources operating at 1300 nm and 1550 nm. Reflected interference signal was acquired by an optical spectrum analyzer while the length of the air cavity was varied. Thickness of the ZnO layers used in the experiments was 50 nm, 100 nm, and 200 nm. Uncoated SMF-28 fiber was also used as a reference. Based on the results of measurements, the thickness of the ZnO layers and the length of the cavity were selected in order to achieve good visibility. Following, the interferometer was used to determine the refractive index of selected liquids.

  4. High Sensitivity Refractometer Based on TiO2-Coated Adiabatic Tapered Optical Fiber via ALD Technology

    Science.gov (United States)

    Zhu, Shan; Pang, Fufei; Huang, Sujuan; Zou, Fang; Guo, Qiang; Wen, Jianxiang; Wang, Tingyun

    2016-01-01

    Atomic layer deposition (ALD) technology is introduced to fabricate a high sensitivity refractometer based on an adiabatic tapered optical fiber. Different thicknesses of titanium dioxide (TiO2) nanofilm were coated around the tapered fiber precisely and uniformly under different deposition cycles. Attributed to the higher refractive index of the TiO2 nanofilm compared to that of silica, an asymmetric Fabry–Perot (F-P) resonator could be constructed along the fiber taper. The central wavelength of the F-P resonator could be controlled by adjusting the thickness of the TiO2 nanofilm. Such a F-P resonator is sensitive to changes in the surrounding refractive index (SRI), which is utilized to realize a high sensitivity refractometer. The refractometer developed by depositing 50.9-nm-thickness TiO2 on the tapered fiber shows SRI sensitivity as high as 7096 nm/RIU in the SRI range of 1.3373–1.3500. Due to TiO2’s advantages of high refractive index, lack of toxicity, and good biocompatibility, this refractometer is expected to have wide applications in the biochemical sensing field. PMID:27537885

  5. Ellipsometry study of process deposition of amorphous Indium Gallium Zinc Oxide sputtered thin films

    Energy Technology Data Exchange (ETDEWEB)

    Talagrand, C., E-mail: talagrand@emse.fr [Ecole des Mines de Saint-Etienne CMP-GC, Dept PS2, Gardanne, 880 route de Mimet (France); Boddaert, X. [Ecole des Mines de Saint-Etienne CMP-GC, Dept PS2, Gardanne, 880 route de Mimet (France); Selmeczi, D.G.; Defranoux, C. [Semilab Semiconductor Physics Laboratory Co. Ltd., Budapest, 1117 (Hungary); Collot, P. [Ecole Nationale Supérieure d' Arts et Métiers ParisTech, Aix-en-Provence, 2 cours des Arts et Métiers (France)

    2015-09-01

    This paper reports on an InGaZnO optical study by spectrometric ellipsometry. First of all, the fitting results of different models and different structures are analysed to choose the most appropriate model. The Tauc–Lorentz model is suitable for thickness measurements but a more complex model allows the refractive index and extinction coefficient to be extracted more accurately. Secondly, different InGaZnO process depositions are carried out in order to investigate stability, influence of deposition time and uniformity. Films present satisfactory optical stability over time. InGaZnO optical property evolution as a function of deposition time is related to an increase in temperature. To understand the behaviour of uniformity, mapping measurements are correlated to thin film resistivity. Results show that temperature and resputtering are the two phenomena that affect IGZO uniformity. - Highlights: • Model and structure are investigated to fit IGZO ellipsometric angles. • Maximum refractive index rises with substrate temperature and thus deposition time. • Resputtering leads to inhomogeneity in IGZO electrical and optical properties.

  6. Oxidation of ZnO thin films during pulsed laser deposition process

    Indian Academy of Sciences (India)

    E De Posada; L Moreira; J Pérez De La Cruz; M Arronte; L V Ponce; T Flores; J G Lunney

    2013-06-01

    Pulsed laser deposition of ZnO thin films, using KrF laser, is analysed. The films were deposited on (001) sapphire substrates at 400 °C, at two different oxygen pressures (0.3 and 0.4 mbar) and two different target–substrate distances (30 and 40 mm). It is observed that in order to obtain good quality in the photoluminescence of the films, associated with oxygen stoichiometry, it is needed to maximize the time during which the plasma remains in contact with the growing film (plasma residence time), which is achieved by selecting suitable combinations of oxygen pressures and target to substrate distances. It is also discussed that for the growth parameters used, the higher probability for ZnO films growth results from the oxidation of Zn deposited on the substrate and such process takes place during the time that the plasma is in contact with the substrate. Moreover, it is observed that maximizing the plasma residence time over the growing film reduces the rate of material deposition, favouring the surface diffusion of adatoms, which favours both Zn–O reaction and grain growth.

  7. Biomimetic formation of titania thin films: effect of amino acids on the deposition process.

    Science.gov (United States)

    Durupthy, Olivier; Jeurgens, Lars P H; Bill, Joachim

    2011-05-01

    Different types of amino acids have been used as additives to control the aqueous deposition of titanium dioxide thin films on single-crystal Si wafers. Thin titania films can be obtained through a chemical bath deposition (CBD) process using TiCl₄ as a precursor in an aqueous solution at temperatures below 100 °C. The addition of amino acids to the deposition solution was shown to reduce the thickness and roughness of the films and to increase their density. These protein building blocks were employed to modify the deposition rate as well as the size of aggregates that form the film. The thickness, crystallinity, morphology and composition of the grown films were characterized by a variety of techniques, including XRD, XPS, AFM and SEM. The consequences of the type of the amino acid additive (and its concentration in the solution) on the microstructural evolutions of the deposed films are thus revealed and discussed on the basis of the organic-inorganic interactions in solution and at the film surface.

  8. Molecular dynamics simulation of the deposition process of hydrogenated diamond-like carbon (DLC) films

    Institute of Scientific and Technical Information of China (English)

    ZHANG YuJun; DONG GuangNeng; MAO JunHong; XIE YouBai

    2008-01-01

    The deposition process of hydrogenated diamond-like carbon (DLC) film greatly affects its frictional properties. In this study, CH3 radicals are selected as source species to deposit hydrogenated DLC films for molecular dynamics simulation. The growth and structural properties of hydrogenated DLC films are investigated and elucidated in detail. By comparison and statistical analysis, the authors find that the ratio of carbon to hydrogen in the films generally shows a monotonously increasing trend with the increase of impact energy. Carbon atoms are more reactive during deposition and more liable to bond with substrate atoms than hydrogen atoms. In addition, there exists a peak value of the number of hydrogen atoms deposited in hydrogenated DLC films. The trends of the variation are opposite on the two sides of this peak point, and itbecomes stable when impact energy is greater than 80 eV. The average relative density also indicates a rising trend along with the increment of impact energy, while it does not reach the saturation value until impact energy comes to 50 eV. The hydrogen content in source species is a key factor to determine the hydrogen content in hydrogenated DLC films. When the hydrogen content in source species is high, the hydrogen content in hydrogenated DLC films is accordingly high.

  9. The interconnection of wet and dry deposition and the alteration of deposition budgets due to incorporation of new process understanding in regional models

    Science.gov (United States)

    Dennis, R. L.; Bash, J. O.; Foley, K. M.; Gilliam, R.; Pinder, R. W.

    2013-12-01

    Deposition is affected by the chemical and physical processes represented in the regional models as well as source strength. The overall production and loss budget (wet and dry deposition) is dynamically connected and adjusts internally to changes in process representation. In addition, the scrubbing of pollutants from the atmosphere by precipitation is one of several processes that remove pollutants, creating a coupling with the atmospheric aqueous and gas phase chemistry that can influence wet deposition rates in a nonlinear manner. We explore through model sensitivities with the regional Community Multiscale Air Quality (CMAQ) model the influence on wet and dry deposition, and the overall continental nitrogen budget, of changes in three process representations in the model: (1) incorporation of lightning generated NO, (2) improved representation of convective precipitation, and (3) replacement of the typical unidirectional dry deposition of NH3 with a state of the science representation of NH3 bi-directional air-surface exchange. Results of the sensitivity studies will be presented. (1) Incorporation of lightning generated NO significantly reduces a negative bias in summer wet nitrate deposition, but is sensitive to the choice of convective parameterization. (2) Use of a less active trigger of convective precipitation in the WRF meteorological model to reduce summertime precipitation over prediction bias reduces the generation of NO from lightning. It also reduces the wet deposition of nitrate and increases the dry deposition of oxidized nitrogen, as well as changing (reducing) the surface level exposure to ozone. Improvements in the convective precipitation processes also result in more non-precipitating clouds leading to an increase in SO4 production through the aqueous pathway resulting in improvements in summertime SO4 ambient aerosol estimates.(3) Incorporation of state of the science ammonia bi-directional air surface exchange affects both the dry

  10. Effect of atomic layer deposition temperature on current conduction in Al2O3 films formed using H2O oxidant

    Science.gov (United States)

    Hiraiwa, Atsushi; Matsumura, Daisuke; Kawarada, Hiroshi

    2016-08-01

    To develop high-performance, high-reliability gate insulation and surface passivation technologies for wide-bandgap semiconductor devices, the effect of atomic layer deposition (ALD) temperature on current conduction in Al2O3 films is investigated based on the recently proposed space-charge-controlled field emission model. Leakage current measurement shows that Al2O3 metal-insulator-semiconductor capacitors formed on the Si substrates underperform thermally grown SiO2 capacitors at the same average field. However, using equivalent oxide field as a more practical measure, the Al2O3 capacitors are found to outperform the SiO2 capacitors in the cases where the capacitors are negatively biased and the gate material is adequately selected to reduce virtual dipoles at the gate/Al2O3 interface. The Al2O3 electron affinity increases with the increasing ALD temperature, but the gate-side virtual dipoles are not affected. Therefore, the leakage current of negatively biased Al2O3 capacitors is approximately independent of the ALD temperature because of the compensation of the opposite effects of increased electron affinity and permittivity in Al2O3. By contrast, the substrate-side sheet of charge increases with increasing ALD temperature above 210 °C and hence enhances the current of positively biased Al2O3 capacitors more significantly at high temperatures. Additionally, an anomalous oscillatory shift of the current-voltage characteristics with ALD temperature was observed in positively biased capacitors formed by low-temperature (≤210 °C) ALD. This shift is caused by dipoles at the Al2O3/underlying SiO2 interface. Although they have a minimal positive-bias leakage current, the low-temperature-grown Al2O3 films cause the so-called blisters problem when heated above 400 °C. Therefore, because of the absence of blistering, a 450 °C ALD process is presently the most promising technology for growing high-reliability Al2O3 films.

  11. Simulation of polyatomic discharges for thin film deposition processes in low-pressure plasma reactors

    Science.gov (United States)

    Bera, Kallol

    conditions of experimental reactors. The discharge models were used to investigate the effects of operating and design parameters of the reactors on plasma process characteristics to obtain better process characteristics on the wafer. These parameters can be used to design new reactors for the deposition/etching process. The models can be modified for different feed gases for other applications like plasma etching or sputtering.

  12. REE concentration processes in ion adsorption deposits: Evidence from Madagascar and China.

    Science.gov (United States)

    Smith, Martin; Estrade, Guillaume; Marquis, Eva; Goodenough, Kathryn; Nasun, Peter; Cheng, Xu; Kynicky, Jindrich

    2017-04-01

    Lateritic clay deposits, where the rare earth elements (REE) occur adsorbed to clay mineral surfaces, are the world's dominant supply of heavy REE (Gd-Lu). These deposits are currently only mined in China where there is a reported heavy REE enrichment, but other deposits are currently under exploration in Brazil, the Philippines and Madagascar. Concentration of REE within IADs has been proposed to be a dominantly supergene process, where easily degradable REE-minerals (e.g. REE-fluorcarbonates) break down and release REE that are then adsorbed to clay minerals resulting in HREE enrichment. Here we present data from the Ambohimirahavavy Complex, Madagascar, and compare them to data from mineralised profiles in China, with the aim of further constraining the formation and REE enrichment processes in ion adsorption deposits. Bulk rock total REE contents from Madagascar vary from 400-5000ppm, with the HREE varying from 10 to 20% of the TREE. Ammonium Sulphate leaches (designed to remove clay-adsorbed REE) of laterite show leachable TREE from 130-500ppm, with no preferential HREE adsorption. Within the sequential extraction procedure the reducible fraction (hydroxylammonium chloride leach) showed the highest REE, but this is largely attributable to Ce4+ in oxide layers. Analysis of laterite profiles show that the REE distribution is heterogeneous, with control from both bedrock heterogeneity, and the hydrological variation between pedolith and saprolith. Similar patterns are seen in Chinese profiles from Jiangxi province. X-ray diffraction shows the clay fraction in all sites is dominated by kaolinite and halloysite. These data are consistent with experimental data which show that kaolinite is only HREE selective in high ionic strength solutions (Coppin et al., 2002), and suggest that HREE enrichment in lateritic deposits may be a function of exceptional bed rock conditions. Petrographic investigation of the Zhaibei granite, immediately underlying HREE enriched

  13. Processing and characterization of high temperature superconductor thin films deposited by electron beam co-evaporation

    Science.gov (United States)

    Huh, Jeong-Uk

    Ever since the high temperature superconductors (HTS) were discovered in the late 1980s, there have been enormous efforts to make this into applications such as power transmission cables, transformers, motors and generators. However, many obstacles in performance and high manufacturing cost made this difficult. The first generation HTS wires had low critical current density and were expensive to fabricate. The motivation of this research was to make high performance and low cost second generation HTS coated conductor. Electron beam co-evaporation technique was used to deposit YBCO(YBa2Cu3O7-x ) film at a high rate (10nm/s and higher) on single crystals and metal tapes. The oxygen pressure at the stage of depositing Y, Ba, Cu was 5x10 -5 Torr and the process temperature was 810-840°C. In-situ Fourier Transform Infrared spectroscopy (FTIR) was used to monitor the optical properties of the YBCO during and after deposition. The deposit transformed to a glassy amorphous mixture of Y, Ba and Cu at 3 mTorr of oxygen. YBCO crystallization occurred after extra oxygen was applied to several Torr. FTIR showed almost the same signature during the formation of YBCO and liquid Ba-Cu-O during deposition, which indicates the liquid played an important role in determining the properties of YBCO in terms of providing epitaxy and fast transport of atoms to nucleate on the film-metal interface. The transformation was very rapid---seconds to minutes, compared to minutes to hours for other post-reaction processes. The oxygen partial pressure and the rate of oxidation (supersaturation) in the liquid region defined in the YBCO phase stability diagram determined the electrical and microstructural properties. In-situ X-ray diffraction heating stage with ambient control was utilized to study this supersaturation effect and explore the temperature-pressure space during YBCO growth. With all the information gathered from FTIR and XRD in-situ experiments and also with nano-engineering during

  14. High aspect ratio iridescent three-dimensional metal–insulator–metal capacitors using atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Burke, Micheal, E-mail: micheal.burke@tyndall.ie; Blake, Alan; Djara, Vladimir; O' Connell, Dan; Povey, Ian M.; Cherkaoui, Karim; Monaghan, Scott; Scully, Jim; Murphy, Richard; Hurley, Paul K.; Pemble, Martyn E.; Quinn, Aidan J., E-mail: aidan.quinn@tyndall.ie [Tyndall National Institute, University College Cork, Cork (Ireland)

    2015-01-01

    The authors report on the structural and electrical properties of TiN/Al{sub 2}O{sub 3}/TiN metal–insulator–metal (MIM) capacitor structures in submicron three-dimensional (3D) trench geometries with an aspect ratio of ∼30. A simplified process route was employed where the three layers for the MIM stack were deposited using atomic layer deposition (ALD) in a single run at a process temperature of 250 °C. The TiN top and bottom electrodes were deposited via plasma-enhanced ALD using a tetrakis(dimethylamino)titanium precursor. 3D trench devices yielded capacitance densities of 36 fF/μm{sup 2} and quality factors >65 at low frequency (200 Hz), with low leakage current densities (<3 nA/cm{sup 2} at 1 V). These devices also show strong optical iridescence which, when combined with the covert embedded capacitance, show potential for system in package (SiP) anticounterfeiting applications.

  15. Atomic Layer Deposition of Silicon Nitride from Bis(tert-butylamino)silane and N2 Plasma.

    Science.gov (United States)

    Knoops, Harm C M; Braeken, Eline M J; de Peuter, Koen; Potts, Stephen E; Haukka, Suvi; Pore, Viljami; Kessels, Wilhelmus M M

    2015-09-01

    Atomic layer deposition (ALD) of silicon nitride (SiNx) is deemed essential for a variety of applications in nanoelectronics, such as gate spacer layers in transistors. In this work an ALD process using bis(tert-butylamino)silane (BTBAS) and N2 plasma was developed and studied. The process exhibited a wide temperature window starting from room temperature up to 500 °C. The material properties and wet-etch rates were investigated as a function of plasma exposure time, plasma pressure, and substrate table temperature. Table temperatures of 300-500 °C yielded a high material quality and a composition close to Si3N4 was obtained at 500 °C (N/Si=1.4±0.1, mass density=2.9±0.1 g/cm3, refractive index=1.96±0.03). Low wet-etch rates of ∼1 nm/min were obtained for films deposited at table temperatures of 400 °C and higher, similar to that achieved in the literature using low-pressure chemical vapor deposition of SiNx at >700 °C. For novel applications requiring significantly lower temperatures, the temperature window from room temperature to 200 °C can be a solution, where relatively high material quality was obtained when operating at low plasma pressures or long plasma exposure times.

  16. What is limiting low-temperature atomic layer deposition of Al{sub 2}O{sub 3}? A vibrational sum-frequency generation study

    Energy Technology Data Exchange (ETDEWEB)

    Vandalon, V., E-mail: v.vandalon@tue.nl, E-mail: w.m.m.kessels@tue.nl; Kessels, W. M. M., E-mail: v.vandalon@tue.nl, E-mail: w.m.m.kessels@tue.nl [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2016-01-04

    The surface reactions during atomic layer deposition (ALD) of Al{sub 2}O{sub 3} from Al(CH{sub 3}){sub 3} and H{sub 2}O have been studied with broadband sum-frequency generation to reveal what is limiting the growth at low temperatures. The –CH{sub 3} surface coverage was measured for temperatures between 100 and 300 °C and the absolute reaction cross sections, describing the reaction kinetics, were determined for both half-cycles. It was found that –CH{sub 3} groups persisted on the surface after saturation of the H{sub 2}O half-cycle. From a direct correlation with the growth per cycle, it was established that the reduced reactivity of H{sub 2}O towards –CH{sub 3} is the dominant factor limiting the ALD process at low temperatures.

  17. Subnanometer Ga 2 O 3 Tunnelling Layer by Atomic Layer Deposition to Achieve 1.1 V Open-Circuit Potential in Dye-Sensitized Solar Cells

    KAUST Repository

    Chandiran, Aravind Kumar

    2012-08-08

    Herein, we present the first use of a gallium oxide tunnelling layer to significantly reduce electron recombination in dye-sensitized solar cells (DSC). The subnanometer coating is achieved using atomic layer deposition (ALD) and leading to a new DSC record open-circuit potential of 1.1 V with state-of-the-art organic D-π-A sensitizer and cobalt redox mediator. After ALD of only a few angstroms of Ga 2O 3, the electron back reaction is reduced by more than an order of magnitude, while charge collection efficiency and fill factor are increased by 30% and 15%, respectively. The photogenerated exciton separation processes of electron injection into the TiO 2 conduction band and the hole injection into the electrolyte are characterized in detail. © 2012 American Chemical Society.

  18. Sub-nanometer atomic layer deposition for spintronics in magnetic tunnel junctions based on graphene spin-filtering membranes.

    Science.gov (United States)

    Martin, Marie-Blandine; Dlubak, Bruno; Weatherup, Robert S; Yang, Heejun; Deranlot, Cyrile; Bouzehouane, Karim; Petroff, Frédéric; Anane, Abdelmadjid; Hofmann, Stephan; Robertson, John; Fert, Albert; Seneor, Pierre

    2014-08-26

    We report on the successful integration of low-cost, conformal, and versatile atomic layer deposited (ALD) dielectric in Ni–Al2O3–Co magnetic tunnel junctions (MTJs) where the Ni is coated with a spin-filtering graphene membrane. The ALD tunnel barriers, as thin as 0.6 nm, are grown layer-by-layer in a simple, low-vacuum, ozone-based process, which yields high-quality electron-transport barriers as revealed by tunneling characterization. Even under these relaxed conditions, including air exposure of the interfaces, a significant tunnel magnetoresistance is measured highlighting the robustness of the process. The spin-filtering effect of graphene is enhanced, leading to an almost fully inversed spin polarization for the Ni electrode of −42%. This unlocks the potential of ALD for spintronics with conformal, layer-by-layer control of tunnel barriers in magnetic tunnel junctions toward low-cost fabrication and down-scaling of tunnel resistances.

  19. Nanocomposite coatings by ALD: in-situ growth investigation and applications (Conference Presentation)

    Science.gov (United States)

    Mane, Anil U.; Elam, Jeffrey W.

    2016-10-01

    We have established ALD methodology to synthesize nanocomposite coatings comprised of conducting, metallic nanoparticles embedded in an amorphous dielectric matrix. These films are nominally composed of M:Al2O3 where (M= W, Mo, and Ta) and are prepared using alternating exposures to trimethyl aluminum (TMA) and H2O for the Al2O3 ALD and alternating MF6/Si2H6 exposures for the metal ALD. By varying the ratio of ALD cycles for the metal and the Al2O3 components during material growth, we can tune precisely the various material properties such as microstructure, electrical, optical and chemical properties. The resistance of these coatings can be controlled over a very broad range (e.g. 1e11-1e4 Ohm-cm) and these films exhibit Ohmic behavior and resist breakdown even at high electric fields of chips) for maskless reflection electron beam lithography system, protective coatings for Li-ion battery cathodes and solar selective absorber coating for high temperature concentrated solar power (CSP). Here we will discuss the ALD in-situ growth study, various nanocomposite material characterizations, and some of these applications.

  20. The fate of SOC during the processes of water erosion and subsequent deposition: a field study.

    Science.gov (United States)

    van Hemelryck, H.; Govers, G.; van Oost, K.; Merckx, R.

    2009-04-01

    Globally soils are the largest terrestrial pool of carbon (C). A relatively small increase or decrease in soil carbon content due to changes in land use or management practices could therefore result in a significant net exchange of C between the soil C reservoir and the atmosphere. As such, the geomorphic processes of water and tillage erosion have been identified to significantly impact on this large pool of soil organic carbon (SOC). Soil erosion, transport and deposition not only result in redistribution of sediments and associated carbon within a landscape, but also affect the exchange of C between the pedosphere and the atmosphere. The direction and magnitude of an erosion-induced change in the global C balance is however a topic of much debate as opposing processes interact: i) At eroding sites a net uptake of C could be the result of reduced respiration rates and continued inputs of newly produced carbon. ii) Colluvial deposition of eroded sediment and SOC leads to the burial of the original topsoil and this may constrain the decomposition of its containing SOC. iii) Eroded sediment could be transported to distal depositional environments or fluvial systems where it will either be conserved or become rapidly mineralized. iv) Increased emission of CO2 due to erosion may result from the disruptive energy of erosive forces causing the breakdown of aggregates and exposing previously protected SOC to microbial decomposition. The above-mentioned processes show a large spatial and temporal variability and assessing their impact requires an integrated modeling approach. However uncertainties about the basic processes that accompany SOC displacement are still large. This study focuses on one of these large information gaps: the fate of eroded and subsequently deposited SOC. A preceding experimental study (Van Hemelryck et al., 2008) was used to identify controlling factors (erosional intensity, changes in soil structure,…). However this experimental research

  1. Oxide-based materials by atomic layer deposition

    Science.gov (United States)

    Godlewski, Marek; Pietruszka, Rafał; Kaszewski, Jarosław; Witkowski, Bartłomiej S.; Gierałtowska, Sylwia; Wachnicki, Łukasz; Godlewski, Michał M.; Slonska, Anna; Gajewski, Zdzisław

    2017-02-01

    Thin films of wide band-gap oxides grown by Atomic Layer Deposition (ALD) are suitable for a range of applications. Some of these applications will be presented. First of all, ALD-grown high-k HfO2 is used as a gate oxide in the electronic devices. Moreover, ALD-grown oxides can be used in memory devices, in transparent transistors, or as elements of solar cells. Regarding photovoltaics (PV), ALD-grown thin films of Al2O3 are already used as anti-reflection layers. In addition, thin films of ZnO are tested as replacement of ITO in PV devices. New applications in organic photovoltaics, electronics and optoelectronics are also demonstrated Considering new applications, the same layers, as used in electronics, can also find applications in biology, medicine and in a food industry. This is because layers of high-k oxides show antibacterial activity, as discussed in this work.

  2. A replacement of high-k process for CMOS transistor by atomic layer deposition

    Science.gov (United States)

    Han, Jin-Woo; Choi, Byung Joon; Yang, J. Joshua; Moon, Dong-Il; Choi, Yang-Kyu; Williams, R. Stanley; Meyyappan, M.

    2013-08-01

    A replacement of high-k process was implemented on an independent double gate FinFET, following the ordinary gate-first process with minor modifications. The present scheme involves neither exotic materials nor unprecedented processing. After the source/drain process, the sacrificial gate oxide was selectively substituted with amorphous Ta2O5 via conformal plasma enhanced atomic layer deposition. The present gate-first gate-dielectric-last scheme combines the advantages of the process and design simplicity of the gate-first approach and the control of the effective gate workfunction and the interfacial oxide of the gate-dielectric-last approach. Electrical characterization data and cross-sectional images are provided as evidence of the concept.

  3. A low-temperature synthesis of electrochemical active Pt nanoparticles and thin films by atomic layer deposition on Si(111) and glassy carbon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Rui [Joint Center for Artificial Photosynthesis, California Institute of Technology, Pasadena, CA 91125 (United States); Han, Lihao [Joint Center for Artificial Photosynthesis, California Institute of Technology, Pasadena, CA 91125 (United States); Photovoltaic Materials and Devices (PVMD) Laboratory, Delft University of Technology, P.O. Box 5031, GA Delft 2600 (Netherlands); Huang, Zhuangqun; Ferrer, Ivonne M. [Joint Center for Artificial Photosynthesis, California Institute of Technology, Pasadena, CA 91125 (United States); Division of Chemistry and Chemical Engineering, California Institute of Technology, 210 Noyes Laboratory 127-72, Pasadena, CA 91125 (United States); Smets, Arno H.M.; Zeman, Miro [Photovoltaic Materials and Devices (PVMD) Laboratory, Delft University of Technology, P.O. Box 5031, GA Delft 2600 (Netherlands); Brunschwig, Bruce S., E-mail: bsb@caltech.edu [Beckman Institute, California Institute of Technology, Pasadena, CA 91125 (United States); Lewis, Nathan S., E-mail: nslewis@caltech.edu [Joint Center for Artificial Photosynthesis, California Institute of Technology, Pasadena, CA 91125 (United States); Beckman Institute, California Institute of Technology, Pasadena, CA 91125 (United States); Division of Chemistry and Chemical Engineering, California Institute of Technology, 210 Noyes Laboratory 127-72, Pasadena, CA 91125 (United States); Kavli Nanoscience Institute, California Institute of Technology, Pasadena, CA 91125 (United States)

    2015-07-01

    Atomic layer deposition (ALD) was used to deposit nanoparticles and thin films of Pt onto etched p-type Si(111) wafers and glassy carbon discs. Using precursors of MeCpPtMe{sub 3} and ozone and a temperature window of 200–300 °C, the growth rate was 80–110 pm/cycle. X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM) were used to analyze the composition, structure, morphology, and thickness of the ALD-grown Pt nanoparticle films. The catalytic activity of the ALD-grown Pt for the hydrogen evolution reaction was shown to be equivalent to that of e-beam evaporated Pt on glassy carbon electrode. - Highlights: • Pure Pt films were grown by atomic layer deposition (ALD) using MeCpPtMe3 and ozone. • ALD-grown Pt thin films had high growth rates of 110 pm/cycle. • ALD-grown Pt films were electrocatalytic for hydrogen evolution from water. • Electrocatalytic activity of the ALD Pt films was equivalent to e-beam deposited Pt. • No carbon species were detected in the ALD-grown Pt films.

  4. One-step electrodeposition process of CuInSe2: Deposition time effect

    Indian Academy of Sciences (India)

    O Meglali; N Attaf; A Bouraiou; M S Aida; S Lakehal

    2014-10-01

    CuInSe2 thin films were prepared by one-step electrodeposition process using a simplified twoelectrodes system. The films were deposited, during 5, 10, 15 and 20 min, from the deionized water solution consisting of CuCl2, InCl3 and SeO2 onto ITO-coated glass substrates. As-deposited films have been annealed under vacuum at 300 °C during 30 min. The structural, optical band gap and electrical resistivity of elaborated films were studied, respectively, using X-ray diffraction (XRD), Raman spectroscopy, UV spectrophotometer and four-point probe method. The micro structural parameters like lattice constants, crystallite size, dislocation density and strain have been evaluated. The XRD investigation proved that the film deposited at 20 min present CuInSe2 single phase in its chalcopyrite structure and with preferred orientation along (1 1 2) direction, whereas the films deposited at 5, 10 and 15 min show the CuInSe2 chalcopyrite structure with the In2Se3 as secondary phase. We have found that the formation mechanism of CuInSe2 depends on the In2Se3 phase. The optical band gap of the films is found to decrease from 1.17 to 1.04 eV with increase in deposition time. All films show Raman spectra with a dominant A1 mode at 174 cm-1, confirming the chalcopyrite crystalline quality of these films. The films exhibited a range of resistivity varying from 2.3 × 10-3 to 4.4 × 10-1 cm.

  5. Synthesis, characterization, and thermal properties of homoleptic rare-earth guanidinates: promising precursors for MOCVD and ALD of rare-earth oxide thin films.

    Science.gov (United States)

    Milanov, Andrian P; Fischer, Roland A; Devi, Anjana

    2008-12-01

    Eight novel homoleptic tris-guanidinato complexes M[(N(i)Pr)(2)CNR(2)](3) [M = Y (a), Gd (b), Dy (c) and R = Me (1), Et (2), (i)Pr (3)] have been synthesized and characterized by NMR, CHN-analysis, mass spectrometry and infrared spectroscopy. Single crystal structure analysis revealed that all the compounds are monomers with the rare-earth metal center coordinated to six nitrogen atoms of the three chelating guanidinato ligands in a distorted trigonal prism geometry. With the use of TGA/DTA and isothermal TGA analysis, the thermal characteristics of all the complexes were studied in detail to evaluate their suitability as precursors for thin film deposition by MOCVD and ALD. The (i)Pr-Me(2)N-guanidinates of Y, Gd and Dy (1a-c) showed excellent thermal characteristics in terms of thermal stability and volatility. Additionally, the thermal stability of the (i)Pr-Me(2)N-guanidinates of Y and Dy (1a, c) in solution was investigated by carrying out NMR decomposition experiments and both the compounds were found to be remarkably stable. All these studies indicate that (i)Pr-Me(2)N-guanidinates of Y, Gd and Dy (1a-c) have the prerequisites for MOCVD and ALD applications which were confirmed by the successful deposition of Gd(2)O(3) and Dy(2)O(3) thin films on Si(100) substrates. The MOCVD grown films of Gd(2)O(3) and Dy(2)O(3) were highly oriented in the cubic phase, while the ALD grown films were amorphous.

  6. Chemically deposited CdS by an ammonia-free process for solar cells window layers

    Energy Technology Data Exchange (ETDEWEB)

    Ochoa-Landin, R. [Centro de Investigacion y Estudios Avanzados del IPN, Unidad Queretaro, Apdo. Postal 1-798, 76001 Queretaro, Qro. (Mexico); Departamento de Fisica, Universidad de Sonora, Apdo. Postal 88, 83190 Hermosillo, Son. (Mexico); Sastre-Hernandez, J.; Vigil-Galan, O. [Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional UP Adolfo Lopez Mateos, Edif. 9, 07738 Mexico, DF (Mexico); Ramirez-Bon, R. [Centro de Investigacion y Estudios Avanzados del IPN, Unidad Queretaro, Apdo. Postal 1-798, 76001 Queretaro, Qro. (Mexico)

    2010-02-15

    Chemically deposited CdS window layers were studied on two different transparent conductive substrates, namely indium tin oxide (ITO) and fluorine doped tin oxide (FTO), to determine the influence of their properties on CdS/CdTe solar cells performance. Three types of CdS films obtained from different chemical bath deposition (CBD) processes were studied. The three CBD processes employed sodium citrate as the complexing agent in partial or full substitution of ammonia. The CdS films were studied by X-ray diffraction, optical transmission spectroscopy and atomic force microscopy. CdS/CdTe devices were completed by depositing 3 {mu}m thick CdTe absorbent layers by means of the close-spaced vapor transport technique (CSVT). Evaporated Cu-Au was used as the back contact in all the solar cells. Dark and under illumination J-V characteristic and quantum efficiency measurements were done on the CdS/CdTe devices to determine their conversion efficiency and spectral response. The efficiency of the cells depended on the window layer and on the transparent contact with values between 5.7% and 8.7%. (author)

  7. Bio-mineralization and potential biogeochemical processes in bauxite deposits: genetic and ore quality significance

    Science.gov (United States)

    Laskou, Magdalini; Economou-Eliopoulos, Maria

    2013-08-01

    The Parnassos-Ghiona bauxite deposit in Greece of karst type is the 11th largest bauxite producer in the world. The mineralogical, major and trace-element contents and δ18O, δ12C, δ34S isotopic compositions of bauxite ores from this deposit and associated limestone provide valuable evidence for their origin and biogeochemical processes resulting in the beneficiation of low grade bauxite ores. The organic matter as thin coal layers, overlying the bauxite deposits, within limestone itself (negative δ12C isotopic values) and the negative δ34S values in sulfides within bauxite ores point to the existence of the appropriate circumstances for Fe bio-leaching and bio-mineralization. Furthermore, a consortium of microorganisms of varying morphological forms (filament-like and spherical to lenticular at an average size of 2 μm), either as fossils or presently living and producing enzymes, is a powerful factor to catalyze the redox reactions, expedite the rates of metal extraction and provide alternative pathways for metal leaching processes resulting in the beneficiation of bauxite ore.

  8. Characterization and prevention of humidity related degradation of atomic layer deposited Al2O3

    Science.gov (United States)

    Rückerl, Andreas; Zeisel, Roland; Mandl, Martin; Costina, Ioan; Schroeder, Thomas; Zoellner, Marvin H.

    2017-01-01

    Atomic layer deposited aluminum oxide (ALD-Al2O3) is a dielectric material, which is widely used in organic light emitting diodes in order to prevent their organic layers from humidity related degradation. Unfortunately, there are strong hints that in some cases, ALD-Al2O3 itself is suffering from humidity related degradation. Especially, high temperature and high humidity seem to enhance ALD-Al2O3 degradation strongly. For this reason, the degradation behavior of ALD-Al2O3 films at high temperature and high humidity was investigated in detail and a way to prevent it from degradation was searched. The degradation behavior is analyzed in the first part of this paper. Using infrared absorbance measurements and X-ray diffraction, boehmite (γ-AlOOH) was identified as a degradation product. In the second part of the paper, it is shown that ALD-Al2O3 films can be effectively protected from degradation using a silicon oxide capping. The deposition of very small amounts of silicon in a molecular beam epitaxy system and an X-ray photoelectron spectroscopy investigation of the chemical bonding between the silicon and the ALD-Al2O3 surface led to the conclusion that a silicon termination of the ALD-Al2O3 surface (Al*-O-SiOx) is able to stop humidity related degradation of the underlying ALD-Al2O3 films. The third part of the paper shows that the protection mechanism of the silicon termination is probably due to the strong tendency of silicic acid to resilificate exposed ALD-Al2O3 surfaces. The protective effect of a simple silicon source on an ALD-Al2O3 surface is shown exemplary and the related chemical reactions are presented.

  9. Investigation of Ag-TiO2 Interfacial Reaction of Highly Stable Ag Nanowire Transparent Conductive Film with Conformal TiO2 Coating by Atomic Layer Deposition.

    Science.gov (United States)

    Yeh, Ming-Hua; Chen, Po-Hsun; Yang, Yi-Ching; Chen, Guan-Hong; Chen, Hsueh-Shih

    2017-03-29

    The atomic layer deposition (ALD) technique is applied to coat Ag nanowires (NWs) with a highly uniform and conformal TiO2 layer to improve the stability and sustainability of Ag NW transparent conductive films (TCFs) at high temperatures. The TiO2 layer can be directly deposited on Ag NWs with a surface polyvinylpyrrolidone (PVP) coat that acts a bed for TiO2 seeding in the ALD process. The ALD TiO2 layer significantly enhances the thermal stability at least 100 fold when aged between 200-400 °C and also provides an extra function of violet-blue light filtration for Ag NW TCFs. Investigation into the interaction between TiO2 and Ag reveals that the conformal TiO2 shell could effectively prevent Ag from 1D-to-3D ripening. However, Ag could penetrate the conformal TiO2 shell and form nanocrystals on the TiO2 shell surface when it is aged at 400 °C. According to experimental data and thermodynamic evaluation, the Ag penetration leads to an interlayer composed of mixed Ag-Ag2O-amorphous carbon phases and TiO2-x at the Ag-TiO2 interface, which is thought to be caused by extremely high vapor pressure of Ag at the Ag-TiO2 interface at a higher temperature (e.g., 400 °C).

  10. Depositional and welding processes in low aspect ratio ignimbrites: examples from the Sulcis Volcanic District(Sardinia, Italy)

    OpenAIRE

    Mulas, Maurizio

    2013-01-01

    The rheomorphic, high-grade, welded ignimbrites are a special type of pyroclastic density current (PDC) deposits usually associated with high intensity volcanic explosive activity (VEI >4). They are characterized by a high variability of physical features and sedimentological structures that may testify different emplacement mechanisms from a PDC and a different response to topography during and after the end of the depositional processes. When the temperatures of the deposits are higher than...

  11. Preparation of Chromium Oxide Coatings on Aluminum Borate Whiskers by a Hydrothermal Deposition Process

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Aluminum borate whiskers (9Al2O32B2O3) can be used to reinforce aluminum alloys to produce light and strong composites. However, the adverse interfacial reactions between the whiskers and the aluminum alloys inhibit their practical uses; therefore, a protective coating is needed on whiskers. In this work, aluminum borate whiskers were coated with chromium-coating deposits in a hydrothermal solution containing CrCl3, Na2C4H4O6, NaPH2O2, and H3BO3. The presence of the impurity P in the hydrothermal deposits can be avoided by reducing the amount of NaPH2O2 in the coating solution. Thermodynamic analysis was used to discuss the behavior of ions in the coating process. The subsequent heating of the hydrothermal products in air at 800 ℃ yielded smooth Cr2O3 films with a thickness of 0.060.07 μm.

  12. Unusual stoichiometry control in the atomic layer deposition of manganese borate films from manganese bis(tris(pyrazolyl)borate) and ozone

    Energy Technology Data Exchange (ETDEWEB)

    Klesko, Joseph P.; Bellow, James A.; Saly, Mark J.; Winter, Charles H., E-mail: chw@chem.wayne.edu [Department of Chemistry, Wayne State University, Detroit, Michigan 48202 (United States); Julin, Jaakko; Sajavaara, Timo [Department of Physics, University of Jyväskylä, 40014 Jyväskylä (Finland)

    2016-09-15

    The atomic layer deposition (ALD) of films with the approximate compositions Mn{sub 3}(BO{sub 3}){sub 2} and CoB{sub 2}O{sub 4} is described using MnTp{sub 2} or CoTp{sub 2} [Tp = tris(pyrazolyl)borate] with ozone. The solid state decomposition temperatures of MnTp{sub 2} and CoTp{sub 2} are ∼370 and ∼340 °C, respectively. Preparative-scale sublimations of MnTp{sub 2} and CoTp{sub 2} at 210 °C/0.05 Torr afforded >99% recoveries with <0.1% nonvolatile residues. Self-limited ALD growth was demonstrated at 325 °C for MnTp{sub 2} or CoTp{sub 2} with ozone as the coreactant. The growth rate for the manganese borate process was 0.19 Å/cycle within the ALD window of 300–350 °C. The growth rate for the cobalt borate process was 0.39–0.42 Å/cycle at 325 °C. X-ray diffraction of the as-deposited films indicated that they were amorphous. Atomic force microscopy of 35–36 nm thick manganese borate films grown within the 300–350 °C ALD window showed root mean square surface roughnesses of 0.4–0.6 nm. Film stoichiometries were assessed by x-ray photoelectron spectroscopy and time of flight-elastic recoil detection analysis. The differing film stoichiometries obtained from the very similar precursors MnTp{sub 2} and CoTp{sub 2} are proposed to arise from the oxidizing ability of the intermediate high valent manganese oxide layers and lack thereof for cobalt.

  13. Use of Plasma Enhanced ALD to Construct Efficient Interference Filters for Astronomy in the FUV - Year 2 Update

    Science.gov (United States)

    Scowen, Paul A.; Nemanich, Robert; Eller, Brianna; Yu, Hongbin; Mooney, Tom; Beasley, Matt

    2017-01-01

    Over the past few years the advent of atomic layer deposition (ALD) technology has opened new capabilities to the field of coatings deposition for use in optical elements. At the same time, there have been major advances in both optical designs and detector technologies that can provide orders of magnitude improvement in throughput in the far ultraviolet (FUV) and near ultraviolet (NUV) passbands. Recent review work has shown that a veritable revolution is about to happen in astronomical diagnostic work for targets ranging from protostellar and protoplanetary systems, to the intergalactic medium that feeds gas supplies for galactic star formation, and supernovae and hot gas from star forming regions that determine galaxy formation feedback. These diagnostics are rooted in access to a forest of emission and absorption lines in the ultraviolet (UV), and all that prevents this advance is the lack of throughput in such systems, even in space-based conditions. We are pursuing an approach to use a range of materials to implement stable optical layers suitable for protective overcoats with high UV reflectivity and unprecedented uniformity, and to use that capability to leverage innovative ultraviolet/optical filter construction to enable astronomical science. These materials will be deposited in a multilayer format over a metal base to produce a stable construct. Specifically, we are employing PEALD (plasma-enhanced atomic layer deposition) methods for the deposition and construction of reflective layers that can be used to construct unprecedented filter designs for use in the ultraviolet. Our paper reports on our work as we enter year 2 of our 3-year program.

  14. A Study on Reactive Spray Deposition Technology Processing Parameters in the Context of Pt Nanoparticle Formation

    Science.gov (United States)

    Roller, Justin M.; Maric, Radenka

    2015-12-01

    Catalytic materials are complex systems in which achieving the desired properties (i.e., activity, selectivity and stability) depends on exploiting the many degrees of freedom in surface and bulk composition, geometry, and defects. Flame aerosol synthesis is a process for producing nanoparticles with ample processing parameter space to tune the desired properties. Flame dynamics inside the reactor are determined by the input process variables such as solubility of precursor in the fuel; solvent boiling point; reactant flow rate and concentration; flow rates of air, fuel and the carrier gas; and the burner geometry. In this study, the processing parameters for reactive spray deposition technology, a flame-based synthesis method, are systematically evaluated to understand the residence times, reactant mixing, and temperature profiles of flames used in the synthesis of Pt nanoparticles. This provides a framework for further study and modeling. The flame temperature and length are also studied as a function of O2 and fuel flow rates.

  15. Atomic layer deposition-Sequential self-limiting surface reactions for advanced catalyst "bottom-up" synthesis

    Science.gov (United States)

    Lu, Junling; Elam, Jeffrey W.; Stair, Peter C.

    2016-06-01

    Catalyst synthesis with precise control over the structure of catalytic active sites at the atomic level is of essential importance for the scientific understanding of reaction mechanisms and for rational design of advanced catalysts with high performance. Such precise control is achievable using atomic layer deposition (ALD). ALD is similar to chemical vapor deposition (CVD), except that the deposition is split into a sequence of two self-limiting surface reactions between gaseous precursor molecules and a substrate. The unique self-limiting feature of ALD allows conformal deposition of catalytic materials on a high surface area catalyst support at the atomic level. The deposited catalytic materials can be precisely constructed on the support by varying the number and type of ALD cycles. As an alternative to the wet-chemistry based conventional methods, ALD provides a cycle-by-cycle "bottom-up" approach for nanostructuring supported catalysts with near atomic precision. In this review, we summarize recent attempts to synthesize supported catalysts with ALD. Nucleation and growth of metals by ALD on oxides and carbon materials for precise synthesis of supported monometallic catalyst are reviewed. The capability of achieving precise control over the particle size of monometallic nanoparticles by ALD is emphasized. The resulting metal catalysts with high dispersions and uniformity often show comparable or remarkably higher activity than those prepared by conventional methods. For supported bimetallic catalyst synthesis, we summarize the strategies for controlling the deposition of the secondary metal selectively on the primary metal nanoparticle but not on the support to exclude monometallic formation. As a review of the surface chemistry and growth behavior of metal ALD on metal surfaces, we demonstrate the ways to precisely tune size, composition and structure of bimetallic metal nanoparticles. The cycle-by-cycle "bottom up" construction of bimetallic (or multiple

  16. [Paste deposition and chip bonding process development]. IBM, Endicott tenth quarterly report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    The scope of Endicott activity during this quarter includes: paste deposition process development and chip bonding process development. It was discovered that small voids exist in the photobumps. These are typically at the base of the bump and are believed to have always been present. Although the reliability test results have been positive and no failure is attributed to voids, the process development work during the last quarter has focused on understanding how these form and how to reduce them. High feed pressure, slow nozzle speed and lower viscosity reduce void formation. Nozzle design changes have been identified. One change will increase the shearing of the paste during feed, thus reducing the viscosity, a second change will allow higher feed pressures. Chip bonding process development has focused on correlating bonding results between the IBM in-house chip bonder made by Research Devices, Inc. and the Universal development bond tool. Two variables have been identified that correlate with poor bond results. The report describes more detail of the activity during the tenth quarter for paste deposition and chip bonding in each of these areas.

  17. Understanding the mechanisms of interfacial reactions during TiO2 layer growth on RuO2 by atomic layer deposition with O2 plasma or H2O as oxygen source

    Science.gov (United States)

    Chaker, A.; Szkutnik, P. D.; Pointet, J.; Gonon, P.; Vallée, C.; Bsiesy, A.

    2016-08-01

    In this paper, TiO2 layers grown on RuO2 by atomic layer deposition (ALD) using tetrakis (dimethyla-mino) titanium (TDMAT) and either oxygen plasma or H2O as oxygen source were analyzed using X-ray diffraction (XRD), Raman spectroscopy, and depth-resolved X-ray Photoelectron spectroscopy (XPS). The main objective is to investigate the surface chemical reactions mechanisms and their influence on the TiO2 film properties. The experimental results using XRD show that ALD deposition using H2O leads to anatase TiO2 whereas a rutile TiO2 is obtained when oxygen-plasma is used as oxygen source. Depth-resolved XPS analysis allows to determine the reaction mechanisms at the RuO2 substrate surface after growth of thin TiO2 layers. Indeed, the XPS analysis shows that when H2O assisted ALD process is used, intermediate Ti2O3 layer is obtained and RuO2 is reduced into Ru as evidenced by high resolution transmission electron microscopy. In this case, there is no possibility to re-oxidize the Ru surface into RuO2 due to the weak oxidation character of H2O and an anatase TiO2 layer is therefore grown on Ti2O3. In contrast, when oxygen plasma is used in the ALD process, its strong oxidation character leads to the re-oxidation of the partially reduced RuO2 following the first Ti deposition step. Consequently, the RuO2 surface is regenerated, allowing the growth of rutile TiO2. A surface chemical reaction scheme is proposed that well accounts for the observed experimental results.

  18. Template-assisted synthesis of III-nitride and metal-oxide nano-heterostructures using low-temperature atomic layer deposition for energy, sensing, and catalysis applications (Presentation Recording)

    Science.gov (United States)

    Biyikli, Necmi; Ozgit-Akgun, Cagla; Eren, Hamit; Haider, Ali; Uyar, Tamer; Kayaci, Fatma; Guler, Mustafa Ozgur; Garifullin, Ruslan; Okyay, Ali K.; Ulusoy, Gamze M.; Goldenberg, Eda

    2015-08-01

    Recent experimental research efforts on developing functional nanostructured III-nitride and metal-oxide materials via low-temperature atomic layer deposition (ALD) will be reviewed. Ultimate conformality, a unique propoerty of ALD process, is utilized to fabricate core-shell and hollow tubular nanostructures on various nano-templates including electrospun nanofibrous polymers, self-assembled peptide nanofibers, metallic nanowires, and multi-wall carbon nanotubes (MWCNTs). III-nitride and metal-oxide coatings were deposited on these nano-templates via thermal and plasma-enhanced ALD processes with thickness values ranging from a few mono-layers to 40 nm. Metal-oxide materials studied include ZnO, TiO2, HfO2, ZrO2, and Al2O3. Standard ALD growth recipes were modified so that precursor molecules have enough time to diffuse and penetrate within the layers/pores of the nano-template material. As a result, uniform and conformal coatings on high-surface area nano-templates were demonstrated. Substrate temperatures were kept below 200C and within the self-limiting ALD window, so that temperature-sensitive template materials preserved their integrity III-nitride coatings were applied to similar nano-templates via plasma-enhanced ALD (PEALD) technique. AlN, GaN, and InN thin-film coating recipes were optimized to achieve self-limiting growth with deposition temperatures as low as 100C. BN growth took place only for >350C, in which precursor decomposition occured and therefore growth proceeded in CVD regime. III-nitride core-shell and hollow tubular single and multi-layered nanostructures were fabricated. The resulting metal-oxide and III-nitride core-shell and hollow nano-tubular structures were used for photocatalysis, dye sensitized solar cell (DSSC), energy storage and chemical sensing applications. Significantly enhanced catalysis, solar efficiency, charge capacity and sensitivity performance are reported. Moreover, core-shell metal-oxide and III-nitride materials

  19. 100GHz Integrated All-Optical Switch Enabled by ALD

    CERN Document Server

    Moille, Gregory; Morgenroth, Laurence; Lehoucq, Gaëlle; Neuilly, François; Hu, Bowen; Decoster, Didier; de Rossi, Alfredo

    2015-01-01

    The carrier lifetime of a photonic crystal all-optical switch is optimized by controlling the surface of GaAs by Atomic Layer Deposition. We demonstrate an all optical modulation capability up to 100GHz at Telecom wavelengths, with a contrast as high as 7dB. Wavelength conversion has also been demonstrated at a repetition rate of 2.5GHz with average pump power of about 0.5mW

  20. Sedimentological characteristics and depositional processes of sediment gravity flows in rift basins: The Palaeogene Dongying and Shahejie formations, Bohai Bay Basin, China

    Science.gov (United States)

    Liu, Lei; Chen, Hongde; Zhong, Yijiang; Wang, Jun; Xu, Changgui; Chen, Anqing; Du, Xiaofeng

    2017-10-01

    Sediment gravity flow deposits are common, particularly in sandy formations, but their origin has been a matter of debate and there is no consensus about the classification of such deposits. However, sediment gravity flow sandstones are economically important and have the potential to meet a growing demand in oil and gas exploration, so there is a drive to better understand them. This study focuses on sediment gravity flow deposits identified from well cores in Palaeogene deposits from the Liaodong Bay Depression in Bohai Bay Basin, China. We classify the sediment gravity flow deposits into eight lithofacies using lithological characteristics, grain size, and sedimentary structures, and interpret the associated depositional processes. Based on the scale, spatial distribution, and contact relationships of sediment gravity flow deposits, we defined six types of lithofacies associations (LAs) that reflect transformation processes and depositional morphology: LA1 (unconfined proximal breccia deposits), LA2 (confined channel deposits), LA3 (braided-channel lobe deposits), LA4 (unconfined lobe deposits), LA5 (distal sheet deposits), and LA6 (non-channelized sheet deposits). Finally, we established three depositional models that reflect the sedimentological characteristics and depositional processes of sediment gravity flow deposits: (1) slope-apron gravel-rich depositional model, which involves cohesive debris flows deposited as LA1 and dilute turbidity currents deposited as LA5; (2) non-channelized surge-like turbidity current depositional model, which mainly comprises sandy slumping, suspended load dominated turbidity currents, and dilute turbidity currents deposited as LA5 and LA6; and (3) channelized subaqueous-fan depositional model, which consists of non-cohesive bedload dominated turbidity currents, suspended load dominated turbidity currents, and dilute turbidity currents deposited as LA2-LA5, originating from sustained extrabasinal turbidity currents

  1. Electrical properties of GaAs metal-oxide-semiconductor structure comprising Al2O3 gate oxide and AlN passivation layer fabricated in situ using a metal-organic vapor deposition/atomic layer deposition hybrid system

    Science.gov (United States)

    Aoki, Takeshi; Fukuhara, Noboru; Osada, Takenori; Sazawa, Hiroyuki; Hata, Masahiko; Inoue, Takayuki

    2015-08-01

    This paper presents a compressive study on the fabrication and optimization of GaAs metal-oxide-semiconductor (MOS) structures comprising a Al2O3 gate oxide, deposited via atomic layer deposition (ALD), with an AlN interfacial passivation layer prepared in situ via metal-organic chemical vapor deposition (MOCVD). The established protocol afforded self-limiting growth of Al2O3 in the atmospheric MOCVD reactor. Consequently, this enabled successive growth of MOCVD-formed AlN and ALD-formed Al2O3 layers on the GaAs substrate. The effects of AlN thickness, post-deposition anneal (PDA) conditions, and crystal orientation of the GaAs substrate on the electrical properties of the resulting MOS capacitors were investigated. Thin AlN passivation layers afforded incorporation of optimum amounts of nitrogen, leading to good capacitance-voltage (C-V) characteristics with reduced frequency dispersion. In contrast, excessively thick AlN passivation layers degraded the interface, thereby increasing the interfacial density of states (Dit) near the midgap and reducing the conduction band offset. To further improve the interface with the thin AlN passivation layers, the PDA conditions were optimized. Using wet nitrogen at 600 °C was effective to reduce Dit to below 2 × 1012 cm-2 eV-1. Using a (111)A substrate was also effective in reducing the frequency dispersion of accumulation capacitance, thus suggesting the suppression of traps in GaAs located near the dielectric/GaAs interface. The current findings suggest that using an atmosphere ALD process with in situ AlN passivation using the current MOCVD system could be an efficient solution to improving GaAs MOS interfaces.

  2. Electrical properties of GaAs metal–oxide–semiconductor structure comprising Al2O3 gate oxide and AlN passivation layer fabricated in situ using a metal–organic vapor deposition/atomic layer deposition hybrid system

    Directory of Open Access Journals (Sweden)

    Takeshi Aoki

    2015-08-01

    Full Text Available This paper presents a compressive study on the fabrication and optimization of GaAs metal–oxide–semiconductor (MOS structures comprising a Al2O3 gate oxide, deposited via atomic layer deposition (ALD, with an AlN interfacial passivation layer prepared in situ via metal–organic chemical vapor deposition (MOCVD. The established protocol afforded self-limiting growth of Al2O3 in the atmospheric MOCVD reactor. Consequently, this enabled successive growth of MOCVD-formed AlN and ALD-formed Al2O3 layers on the GaAs substrate. The effects of AlN thickness, post-deposition anneal (PDA conditions, and crystal orientation of the GaAs substrate on the electrical properties of the resulting MOS capacitors were investigated. Thin AlN passivation layers afforded incorporation of optimum amounts of nitrogen, leading to good capacitance–voltage (C–V characteristics with reduced frequency dispersion. In contrast, excessively thick AlN passivation layers degraded the interface, thereby increasing the interfacial density of states (Dit near the midgap and reducing the conduction band offset. To further improve the interface with the thin AlN passivation layers, the PDA conditions were optimized. Using wet nitrogen at 600 °C was effective to reduce Dit to below 2 × 1012 cm−2 eV−1. Using a (111A substrate was also effective in reducing the frequency dispersion of accumulation capacitance, thus suggesting the suppression of traps in GaAs located near the dielectric/GaAs interface. The current findings suggest that using an atmosphere ALD process with in situ AlN passivation using the current MOCVD system could be an efficient solution to improving GaAs MOS interfaces.

  3. New deposition processes for the growth of oxide and nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Apen, E.A.; Atagi, L.M.; Barbero, R.S.; Espinoza, B.F.; Hubbard, K.M.; Salazar, K.V.; Samuels, J.A.; Smith, D.C. [Los Alamos National Lab., NM (US); Hoffman, D.M. [Univ. of Houston, TX (US)

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The goal of this effort is to study the use of homoleptic metal amido compounds as precursors for chemical vapor deposition (CVD). The amides offer potential for the deposition of a variety of important materials at low temperatures. The establishment of these precursor compounds will enhance the ability to exploit the properties of advanced materials in numerous coatings applications. Experiments were performed to study the reactivity of Sn[NMe{sub 2}]{sub 4} with oxygen. The data demonstrated that gas-phase insertion of oxygen into the Sn-N bond, leading to a reactive intermediate, plays an important role in tin oxide deposition. Several CVD processes for technologically important materials were developed using the amido precursor complexes. These included the plasma enhanced CVD of TiN and Zr{sub 3}N{sub 4}, and the thermal CVD of GaN and Al N. Quality films were obtained in each case, demonstrating the potential of the amido compounds as CVD precursors.

  4. Influence of flocculation on sediment deposition process at the Three Gorges Reservoir.

    Science.gov (United States)

    Wang, Dangwei; Liu, Xiaofang; Ji, Zuwen; Dong, Zhandi; Hu, Haihua

    2016-01-01

    By comparing the original particle gradation of sediment from the Three Gorges Reservoir with the single particle gradation, the differences in these two particle gradations showed that there is sediment flocculation in the Three Gorges Reservoir, which can accelerate the sediment deposition rate in the reservoir. In order to determine the influence of flocculation on the sediment settling velocity, sediment was collected at the Three Gorges Reservoir, and the indoor quiescent settling experiment was performed to study the mechanism of sediment flocculation. The experimental results showed that sediments aggregated from single particles into floccules in the settling processes. The single particles smaller than 0.022 mm will participate in the formation of floccules, which accounts for 83% of the total amount of sediment in the Three Gorges Reservoir. Moreover, the degree of sediment flocculation and the increase in sediment settling velocity were directly proportional to the sediment concentration. Taking the average particle size and the median particle size as the representative particle size, respectively, the maximum flocculation factors were calculated to be 3.4 and 5.0. Due to the sediment flocculation, the volume of sediment deposition will increase by 66% when the mass settling flux factor of total sediment had a maximum value of 1.66, suggesting that flocculation has a significant influence on the sediment deposition rate in the Three Gorges Reservoir.

  5. What processes at mid-ocean ridges tell us about volcanogenic massive sulfide deposits

    Science.gov (United States)

    Cathles, Lawrence M.

    2011-07-01

    Episodic seafloor spreading, ridge topography, and fault movement at ridges find (more extreme) analogs in the arc and back-arc setting where the volcanogenic massive sulfide (VMS) deposits that we mine today were formed. The factors affecting sulfide accumulation efficiency and the extent to which sulfides are concentrated spatially are the same in both settings, however. The processes occurring at mid-ocean ridges therefore provide a useful insight into those producing VMS deposits in arcs and back-arcs. The critical observation investigated here is that all the heat introduced by seafloor spreading at mid-ocean ridges is carried out of the crust within a few hundred meters of the ridge axis by ˜350°C hydrothermal fluids. The high-temperature ridge hydrothermal systems are tied to the presence of magma at the ridge axis and greatly reduce the size and control the shape of axial magma intrusions. The amount of heat introduced to each square kilometer of ocean crust during its formation can be calculated, and its removal by high-temperature convection allows calculation of the total base metal endowment of the ocean basins. Using reasonable metal deposition efficiencies, we conclude that the ocean floor is a giant VMS district with metal resources >600 times the total known VMS reserves on land and a copper resource which would last >6,000 years at current production rates.

  6. Tuning polymorphism and orientation in organic semiconductor thin films via post-deposition processing.

    Science.gov (United States)

    Hiszpanski, Anna M; Baur, Robin M; Kim, Bumjung; Tremblay, Noah J; Nuckolls, Colin; Woll, Arthur R; Loo, Yueh-Lin

    2014-11-05

    Though both the crystal structure and molecular orientation of organic semiconductors are known to impact charge transport in thin-film devices, separately accessing different polymorphs and varying the out-of-plane molecular orientation is challenging, typically requiring stringent control over film deposition conditions, film thickness, and substrate chemistry. Here we demonstrate independent tuning of the crystalline polymorph and molecular orientation in thin films of contorted hexabenzocoronene, c-HBC, during post-deposition processing without the need to adjust deposition conditions. Three polymorphs are observed, two of which have not been previously reported. Using our ability to independently tune the crystal structure and out-of-plane molecular orientation in thin films of c-HBC, we have decoupled and evaluated the effects that molecular packing and orientation have on device performance in thin-film transistors (TFTs). In the case of TFTs comprising c-HBC, polymorphism and molecular orientation are equally important; independently changing either one affects the field-effect mobility by an order of magnitude.

  7. Half-sandwich cobalt complexes in the metal-organic chemical vapor deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Georgi, Colin [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Hapke, Marko; Thiel, Indre [Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT), Albert-Einstein-Straße 29a, Rostock 18059 (Germany); Hildebrandt, Alexander [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Waechtler, Thomas; Schulz, Stefan E. [Fraunhofer Institute of Electronic Nano Systems (ENAS), Technologie-Campus 3, Chemnitz 09126 (Germany); Technische Universität Chemnitz, Center for Microtechnologies (ZfM), Chemnitz 09107 (Germany); Lang, Heinrich, E-mail: heinrich.lang@chemie.tu-chemnitz.de [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany)

    2015-03-02

    A series of cobalt half-sandwich complexes of type [Co(η{sup 5}-C{sub 5}H{sub 5})(L)(L′)] (1: L, L′ = 1,5-hexadiene; 2: L = P(OEt){sub 3}, L′ = H{sub 2}C=CHSiMe{sub 3}; 3: L = L′ = P(OEt){sub 3}) has been studied regarding their physical properties such as the vapor pressure, decomposition temperature and applicability within the metal-organic chemical vapor deposition (MOCVD) process, with a focus of the influence of the phosphite ligands. It could be shown that an increasing number of P(OEt){sub 3} ligands increases the vapor pressure and thermal stability of the respective organometallic compound. Complex 3 appeared to be a promising MOCVD precursor with a high vapor pressure and hence was deposited onto Si/SiO{sub 2} (100 nm) substrates. The resulting reflective layer is closed, dense and homogeneous, with a slightly granulated surface morphology. X-ray photoelectron spectroscopy (XPS) studies demonstrated the formation of metallic cobalt, cobalt phosphate, cobalt oxide and cobalt carbide. - Highlights: • Thermal studies and vapor pressure measurements of cobalt half-sandwich complexes was carried out. • Chemical vapor deposition with cobalt half-sandwich complexes is reported. • The use of Co-phosphites results in significant phosphorous-doped metallic layers.

  8. RESEARCH ON LASER DIRECT DEPOSITION PROCESS OF Ti-6Al-4V ALLOY

    Institute of Scientific and Technical Information of China (English)

    S.Y. Gao; Y.Z. Zhang; L.K. Shi; B.L. Du; M.Z. Xi; H.Z. Ji

    2007-01-01

    Laser direct deposition (LDD) of metallic components is an advanced technology of combining CAD/CAM (computer aided design/computer aided manufacturing), high power laser, and rapid prototyping. This technology uses laser beam to melt the powders fed coaxially into the molten pool by the laser beam to fabricate fully dense metallic components. The present article mainly studies the LDD of Ti-6Al-4V alloy, which can be used to fabricate aircraft components. The mechanical properties of the Ti-6Al-4V alloy, fabricated by LDD, are obtained using the tension test, and the oxygen content of used powders and deposited specimens are measured. In the present article, it can be seen that the mechanical properties obtained using this method are higher than the ones obtained by casting, and equal to those got by wrought anneal. One aircraft pan has been made using the LDD process. Because of this aircraft part, with sophisticated shape, the effect of the laser scanning track on the internal soundness of the deposited part was discussed.

  9. Preparation of gallium nitride surfaces for atomic layer deposition of aluminum oxide.

    Science.gov (United States)

    Kerr, A J; Chagarov, E; Gu, S; Kaufman-Osborn, T; Madisetti, S; Wu, J; Asbeck, P M; Oktyabrsky, S; Kummel, A C

    2014-09-14

    A combined wet and dry cleaning process for GaN(0001) has been investigated with XPS and DFT-MD modeling to determine the molecular-level mechanisms for cleaning and the subsequent nucleation of gate oxide atomic layer deposition (ALD). In situ XPS studies show that for the wet sulfur treatment on GaN(0001), sulfur desorbs at room temperature in vacuum prior to gate oxide deposition. Angle resolved depth profiling XPS post-ALD deposition shows that the a-Al2O3 gate oxide bonds directly to the GaN substrate leaving both the gallium surface atoms and the oxide interfacial atoms with XPS chemical shifts consistent with bulk-like charge. These results are in agreement with DFT calculations that predict the oxide/GaN(0001) interface will have bulk-like charges and a low density of band gap states. This passivation is consistent with the oxide restoring the surface gallium atoms to tetrahedral bonding by eliminating the gallium empty dangling bonds on bulk terminated GaN(0001).

  10. Passivation Effect of Atomic Layer Deposition of Al2O3 Film on HgCdTe Infrared Detectors

    Science.gov (United States)

    Zhang, Peng; Ye, Zhen-Hua; Sun, Chang-Hong; Chen, Yi-Yu; Zhang, Tian-Ning; Chen, Xin; Lin, Chun; Ding, Ring-Jun; He, Li

    2016-09-01

    The passivation effect of atomic layer deposition of (ALD) Al2O3 film on a HgCdTe infrared detector was investigated in this work. The passivation effect of Al2O3 film was evaluated by measuring the minority carrier lifetime, capacitance versus voltage ( C- V) characteristics of metal-insulator-semiconductor devices, and resistance versus voltage ( R- V) characteristics of variable-area photodiodes. The minority carrier lifetime, C- V characteristics, and R- V characteristics of HgCdTe devices passivated by ALD Al2O3 film was comparable to those of HgCdTe devices passivated by e-beam evaporation of ZnS/CdTe film. However, the baking stability of devices passivated by Al2O3 film is inferior to that of devices passivated by ZnS/CdTe film. In future work, by optimizing the ALD Al2O3 film growing process and annealing conditions, it may be feasible to achieve both excellent electrical properties and good baking stability.

  11. Two-Dimensional Electron Gas at SrTiO3-Based Oxide Heterostructures via Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Sang Woon Lee

    2016-01-01

    Full Text Available Two-dimensional electron gas (2DEG at an oxide interface has been attracting considerable attention for physics research and nanoelectronic applications. Early studies reported the formation of 2DEG at semiconductor interfaces (e.g., AlGaAs/GaAs heterostructures with interesting electrical properties such as high electron mobility. Besides 2DEG formation at semiconductor junctions, 2DEG was realized at the interface of an oxide heterostructure such as the LaAlO3/SrTiO3 (LAO/STO heterojunction. The origin of 2DEG was attributed to the well-known “polar catastrophe” mechanism in oxide heterostructures, which consist of an epitaxial LAO layer on a single crystalline STO substrate among proposed mechanisms. Recently, it was reported that the creation of 2DEG was achieved using the atomic layer deposition (ALD technique, which opens new functionality of ALD in emerging nanoelectronics. This review is focused on the origin of 2DEG at oxide heterostructures using the ALD process. In particular, it addresses the origin of 2DEG at oxide interfaces based on an alternative mechanism (i.e., oxygen vacancies.

  12. Impact of hydrotalcite deposition on biogeochemical processes in a shallow tropical bay.

    Science.gov (United States)

    Alongi, Daniel M; McKinnon, A David

    2011-03-01

    The biogeochemistry of a tropical shoal bay (Melville Bay, Australia) impacted by the effluent release, precipitation, and deposition of hydrotalcite from an alumina refinery was studied in both wet and dry seasons. Within the deposition zone, sulfate reduction dominated benthic carbon cycling accounting for ≈100% of total microbial activity, with rates greater than those measured in most other marine sediments. These rapid rates of anoxic metabolism resulted in high rates of sulfide and ammonium production and low C:S ratios, implying significant preservation of S in stable sulfide minerals. Rates of total microbial activity were significantly less in control sediments of equivalent grain size, where sulfate reduction accounted for ≈50% of total benthic metabolism. Rates of planktonic carbon cycling overlying the deposition zone were also greater than those measured in the control areas of southern Melville Bay. At the sediment surface, productive algal and cyanobacterial mats helped stabilize the sediment surface and oxidize sulfide to sulfate to maintain a fully oxygenated water-column overlying the impacted zone. The mats utilized a significant fraction of dissolved inorganic N and P released from the sea bed; some nutrients escaped to the water-column such that benthic regeneration of NH₄+ and PO₄³⁻ accounted for 100% and 42% of phytoplankton requirements for N and P, respectively. These percentages are high compared to other tropical coastal environments and indicate that benthic nutrient recycling may be a significant factor driving water-column production overlying the deposition zone. With regard to remediation, it is recommended that the sea bed not be disturbed as attempts at removal may result in further environmental problems and would require specific assessment of the proposed removal process.

  13. Textural and depositional processes of surface sediments of Kalpakkam, Southeast Coast of India

    Institute of Scientific and Technical Information of China (English)

    Usha NATESAN; K.Deepthi; AL.MUTHULAKSHMI; Vincent A.FERRER; S.V.NARASIMHAN; V.P.VENUGOPALAN

    2012-01-01

    To understand the influence of human disturbance on the sediment processes along Kalpakkam coast,India,beach and seabed sediments at 200 m,500 m,and 1 km into the sea were collected monthly for one year and analyzed.Coarser material close to the tidal inlets (river) and manmade structures (sea wall) indicate the effect of these features in altering the grain size distribution from the general trend.The bivariant plots confirm the dominance of deposition under beach environment.The CM diagram (C-one percentile grain diameter,M-median) divulges that the deposition takes place by suspension and rolling of sediments with C < 1 mm.Linear discriminate function analysis for sediments at Kalpakkam indicates a shallow marine environment for all the samples collected.On the multigroup multivariant discriminant functions V1-V2 diagram,the bulk of the samples from Kalpakkam to Mahabalipuram fall in the field of beach deposition.These results show that reworked sediments,submerged during the Holocene marine transgression are being deposited on present-day beaches by waves,currents and rivers in the study area.Though a high wave energy environment is prevailing in the study area,dominant northward sediment transport along the Kalpakkam-Mahabalipuram coast is not altered due to human interventions.Beach building activity in front of the sea wall ensures the safety ofIndira Gandhi Centre for Atomic Research (IGCAR) from wave actions without causing any significant changes to the coastal environment.

  14. Atomic layer deposition: an enabling technology for the growth of functional nanoscale semiconductors

    Science.gov (United States)

    Biyikli, Necmi; Haider, Ali

    2017-09-01

    In this paper, we present the progress in the growth of nanoscale semiconductors grown via atomic layer deposition (ALD). After the adoption by semiconductor chip industry, ALD became a widespread tool to grow functional films and conformal ultra-thin coatings for various applications. Based on self-limiting and ligand-exchange-based surface reactions, ALD enabled the low-temperature growth of nanoscale dielectric, metal, and semiconductor materials. Being able to deposit wafer-scale uniform semiconductor films at relatively low-temperatures, with sub-monolayer thickness control and ultimate conformality, makes ALD attractive for semiconductor device applications. Towards this end, precursors and low-temperature growth recipes are developed to deposit crystalline thin films for compound and elemental semiconductors. Conventional thermal ALD as well as plasma-assisted and radical-enhanced techniques have been exploited to achieve device-compatible film quality. Metal-oxides, III-nitrides, sulfides, and selenides are among the most popular semiconductor material families studied via ALD technology. Besides thin films, ALD can grow nanostructured semiconductors as well using either template-assisted growth methods or bottom-up controlled nucleation mechanisms. Among the demonstrated semiconductor nanostructures are nanoparticles, nano/quantum-dots, nanowires, nanotubes, nanofibers, nanopillars, hollow and core-shell versions of the afore-mentioned nanostructures, and 2D materials including transition metal dichalcogenides and graphene. ALD-grown nanoscale semiconductor materials find applications in a vast amount of applications including functional coatings, catalysis and photocatalysis, renewable energy conversion and storage, chemical sensing, opto-electronics, and flexible electronics. In this review, we give an overview of the current state-of-the-art in ALD-based nanoscale semiconductor research including the already demonstrated and future applications.

  15. Deposition of calcium carbonate films by a polymer-induced liquid-precursor (PILP) process

    Science.gov (United States)

    Gower, Laurie B.; Odom, Damian J.

    2000-03-01

    A polypeptide additive has been used to transform the solution crystallization of calcium carbonate to a solidification process of a liquid-phase mineral precursor. In situ observations reveal that polyaspartate induces liquid-liquid phase separation of droplets of a mineral precursor. The droplets deposit on the substrate and coalesce to form a coating, which then solidifies into calcitic tablets and films. Transition bars form during the amorphous to crystalline transition, leading to sectorization of calcite tablets, and the defect textures and crystal morphologies are atypical of solution grown crystals. The formation of nonequilibrium crystal morphologies using an acidic polypeptide may have implications in the field of biomineralization, and the environmentally friendly aspects of this polymer-induced liquid-precursor (PILP) process may offer new techniques for aqueous-based processing of ceramic films, coatings, and particulates.

  16. Pulsed laser deposition of the lysozyme protein: an unexpected “Inverse MAPLE” process

    DEFF Research Database (Denmark)

    Schou, Jørgen; Matei, Andreea; Constantinescu, Catalin

    2012-01-01

    the ejection and deposition of lysozyme. This can be called an “inverse MAPLE” process, since the ratio of “matrix” to film material in the target is 10:90, which is inverse of the typical MAPLE process where the film material is dissolved in the matrix down to several wt.%. Lysozyme is a well-known protein...... which is used in food processing and is also an important constituent of human secretions such as sweat and saliva. It has a well-defined mass (14307 u) and can easily be detected by mass spectrometric methods such as MALDI (Matrix-assisted laser desorption ionization) in contrast to many other organic...

  17. Chemical characterisation of rainwater at Stromboli Island (Italy): The effect of post-depositional processes

    Science.gov (United States)

    Cangemi, Marianna; Madonia, Paolo; Favara, Rocco

    2017-04-01

    Volcanoes emit fluids and solid particles into the atmosphere that modify the chemical composition of natural precipitation. We have investigated the geochemistry of Stromboli's rainfall during the period from November 2014 to March 2016 using a network of a new type of sampler specifically designed for operations on volcanic islands. We found that most of the chemical modifications are due to processes occurring after the storage of rainwater in the sampling bottles. These processes include dissolution of volcanogenic soluble salts encrusting volcanic ash and a variable contribution of sea spray aerosol. Our data showed noticeably less scatter than has previously been achieved with a different sampling system that was more open to the atmosphere. This demonstrates the improved efficacy of the new sampler design. The data showed that post-depositional chemical alteration of rain samples dominates over processes occurring during droplet formation ad precipitation. This has important implications for the calculation of fluxes of chemicals from rainfall in volcanic regions.

  18. Chemical vapor deposition graphene transfer process to a polymeric substrate assisted by a spin coater

    Science.gov (United States)

    Kessler, Felipe; da Rocha, Caique O. C.; Medeiros, Gabriela S.; Fechine, Guilhermino J. M.

    2016-03-01

    A new method to transfer chemical vapor deposition graphene to polymeric substrates is demonstrated here, it is called direct dry transfer assisted by a spin coater (DDT-SC). Compared to the conventional method DDT, the improvement of the contact between graphene-polymer due to a very thin polymeric film deposited by spin coater before the transfer process prevented air bubbles and/or moisture and avoided molecular expansion on the graphene-polymer interface. An acrylonitrile-butadiene-styrene copolymer, a high impact polystyrene, polybutadiene adipate-co-terephthalate, polylactide acid, and a styrene-butadiene-styrene copolymer are the polymers used for the transfers since they did not work very well by using the DDT process. Raman spectroscopy and optical microscopy were used to identify, to quantify, and to qualify graphene transferred to the polymer substrates. The quantity of graphene transferred was substantially increased for all polymers by using the DDT-SC method when compared with the DDT standard method. After the transfer, the intensity of the D band remained low, indicating low defect density and good quality of the transfer. The DDT-SC transfer process expands the number of graphene applications since the polymer substrate candidates are increased.

  19. Synthesis of magnetic tunnel junctions with full in situ atomic layer and chemical vapor deposition processes

    Energy Technology Data Exchange (ETDEWEB)

    Mantovan, R., E-mail: roberto.mantovan@mdm.imm.cnr.it [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate Brianza (Italy); Vangelista, S.; Kutrzeba-Kotowska, B.; Cocco, S.; Lamperti, A.; Tallarida, G. [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate Brianza (MB) (Italy); Mameli, D. [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate Brianza (Italy); Dipartimento di Scienze Chimiche, Universita di Cagliari, Cittadella Universitaria, 09042 Monserrato, Cagliari (Italy); Fanciulli, M. [Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate Brianza (Italy); Dipartimento di Scienza dei Materiali, Universita degli studi Milano-Bicocca, Via R Cozzi 53, 20125 Milano (Italy)

    2012-05-01

    Magnetic tunnel junctions, i.e. the combination of two ferromagnetic electrodes separated by an ultrathin tunnel oxide barrier, are core elements in a large variety of spin-based devices. We report on the use of combined chemical vapor and atomic layer deposition processes for the synthesis of magnetic tunnel junctions with no vacuum break. Structural, chemical and morphological characterizations of selected ferromagnetic and oxide layers are reported, together with the evidence of tunnel magnetoresistance effect in patterned Fe/MgO/Co junctions.

  20. Self-catalytic growth of tin oxide nanowires by chemical vapor deposition process

    CSIR Research Space (South Africa)

    Thabethe, BS

    2013-01-01

    Full Text Available Corporation Journal of Nanomaterials Volume 2013, Article ID 712361, 7 pages http://dx.doi.org/10.1155/2013/712361 Research Article Self-Catalytic Growth of Tin Oxide Nanowires by Chemical Vapor Deposition Process Bongani S. Thabethe,1,2 Gerald F. Malgas,1... Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa Correspondence should be addressed to Gerald F. Malgas; gmalgas@csir.co.za and David E. Motaung; dmotaung@csir.co.za Received 20 February 2013; Accepted 10...

  1. Parametric study of an HVOF process for the deposition of nanostructured WC-Co coatings

    Science.gov (United States)

    Bartuli, Cecilia; Valente, Teodoro; Cipri, Fabio; Bemporad, Edoardo; Tului, Mario

    2005-06-01

    Nanocrystalline WC-Co coatings were deposited by high velocity oxyfuel from commercial nanostructured composite powders. Processing parameters were optimized for maximal retention of the nanocrystalline size and for minimal decarburation of the ceramic reinforcement. Thermochemical and gas-dynamical properties of gas and particle flows within the combustion flame were identified in various operating conditions by computational fluid-dynamics (CFD) simulation. Significant improvements of the mechanical properties of the coatings were obtained: a decrease of the friction coefficient was measured for the nanostructured coatings, together with an increase of microhardness and fracture toughness.

  2. Base surge deposits, eruption history, and depositional processes of a wet phreatomagmatic volcano in Central Anatolia (Cora Maar)

    Science.gov (United States)

    Gençalioğlu-Kuşcu, Gonca; Atilla, Cüneyt; Cas, Ray A. F.; Kuşcu, İlkay

    2007-01-01

    Cora Maar is a Quaternary volcano located to the 20 km northwest of Mount Erciyes, the largest of the 19 polygenetic volcanic complexes of the Cappadocian Volcanic Province in central Anatolia. Cora Maar is a typical example of a maar-diatreme volcano with a nearly circular crater with a mean diameter of c.1.2 km, and a well-bedded base surge-dominated maar rim tephra sequence up to 40 m in thickness. Having a diameter/depth ratio ( D/ d) of 12, Cora is a relatively "mature" maar compared to recent maar craters in the world. Cora crater is excavated within the andesitic lava flows of Quaternary age. The tephra sequence is not indurated, and consists of juvenile clasts up to 70 cm, non-juvenile clasts up to 130 cm, accretionary lapilli up to 1.2 cm in diameter, and ash to lapilli-sized tephra. Base surge layers display well-developed antidune structures indicating the direction of the transport. Both progressive and regressive dune structures are present within the tephra sequence. Wavelength values increase with increasing wave height, and with large wavelength and height values. Cora tephra display similarities to Taal and Laacher See base surge deposits. Impact sags and small channel structures are also common. Lateral and vertical facies changes are observed for the dune bedded and planar bedsets. According to granulometric analyses, Cora Maar tephra samples display a bimodal distribution with a wide range of Md φ values, characteristic for the surge deposits. Very poorly sorted, bimodal ash deposits generally vary from coarse tail to fine tail grading depending on the grain size distribution while very poorly sorted lapilli and block-rich deposits display a positive skewness due to fine tail grading.

  3. A brief review of atomic layer deposition: from fundamentals to applications

    Directory of Open Access Journals (Sweden)

    Richard W. Johnson

    2014-06-01

    Full Text Available Atomic layer deposition (ALD is a vapor phase technique capable of producing thin films of a variety of materials. Based on sequential, self-limiting reactions, ALD offers exceptional conformality on high-aspect ratio structures, thickness control at the Angstrom level, and tunable film composition. With these advantages, ALD has emerged as a powerful tool for many industrial and research applications. In this review, we provide a brief introduction to ALD and highlight select applications, including Cu(In,GaSe2 solar cell devices, high-k transistors, and solid oxide fuel cells. These examples are chosen to illustrate the variety of technologies that are impacted by ALD, the range of materials that ALD can deposit – from metal oxides such as Zn1−xSnxOy, ZrO2, Y2O3, to noble metals such as Pt – and the way in which the unique features of ALD can enable new levels of performance and deeper fundamental understanding to be achieved.

  4. Sealing of hard CrN and DLC coatings with atomic layer deposition.

    Science.gov (United States)

    Härkönen, Emma; Kolev, Ivan; Díaz, Belén; Swiatowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Marcus, Philippe; Fenker, Martin; Toth, Lajos; Radnoczi, György; Vehkamäki, Marko; Ritala, Mikko

    2014-02-12

    Atomic layer deposition (ALD) is a thin film deposition technique that is based on alternating and saturating surface reactions of two or more gaseous precursors. The excellent conformality of ALD thin films can be exploited for sealing defects in coatings made by other techniques. Here the corrosion protection properties of hard CrN and diamond-like carbon (DLC) coatings on low alloy steel were improved by ALD sealing with 50 nm thick layers consisting of Al2O3 and Ta2O5 nanolaminates or mixtures. In cross sectional images the ALD layers were found to follow the surface morphology of the CrN coatings uniformly. Furthermore, ALD growth into the pinholes of the CrN coating was verified. In electrochemical measurements the ALD sealing was found to decrease the current density of the CrN coated steel by over 2 orders of magnitude. The neutral salt spray (NSS) durability was also improved: on the best samples the appearance of corrosion spots was delayed from 2 to 168 h. On DLC coatings the adhesion of the ALD sealing layers was weaker, but still clear improvement in NSS durability was achieved indicating sealing of the pinholes.

  5. 3D-nanoarchitectured Pd/Ni catalysts prepared by atomic layer deposition for the electrooxidation of formic acid

    Directory of Open Access Journals (Sweden)

    Loïc Assaud

    2014-02-01

    Full Text Available Three-dimensionally (3D nanoarchitectured palladium/nickel (Pd/Ni catalysts, which were prepared by atomic layer deposition (ALD on high-aspect-ratio nanoporous alumina templates are investigated with regard to the electrooxidation of formic acid in an acidic medium (0.5 M H2SO4. Both deposition processes, Ni and Pd, with various mass content ratios have been continuously monitored by using a quartz crystal microbalance. The morphology of the Pd/Ni systems has been studied by electron microscopy and shows a homogeneous deposition of granularly structured Pd onto the Ni substrate. X-ray diffraction analysis performed on Ni and NiO substrates revealed an amorphous structure, while the Pd coating crystallized into a fcc lattice with a preferential orientation along the [220]-direction. Surface chemistry analysis by X-ray photoelectron spectroscopy showed both metallic and oxide contributions for the Ni and Pd deposits. Cyclic voltammetry of the Pd/Ni nanocatalysts revealed that the electrooxidation of HCOOH proceeds through the direct dehydrogenation mechanism with the formation of active intermediates. High catalytic activities are measured for low masses of Pd coatings that were generated by a low number of ALD cycles, probably because of the cluster size effect, electronic interactions between Pd and Ni, or diffusion effects.

  6. 3D-nanoarchitectured Pd/Ni catalysts prepared by atomic layer deposition for the electrooxidation of formic acid.

    Science.gov (United States)

    Assaud, Loïc; Monyoncho, Evans; Pitzschel, Kristina; Allagui, Anis; Petit, Matthieu; Hanbücken, Margrit; Baranova, Elena A; Santinacci, Lionel

    2014-01-01

    Three-dimensionally (3D) nanoarchitectured palladium/nickel (Pd/Ni) catalysts, which were prepared by atomic layer deposition (ALD) on high-aspect-ratio nanoporous alumina templates are investigated with regard to the electrooxidation of formic acid in an acidic medium (0.5 M H2SO4). Both deposition processes, Ni and Pd, with various mass content ratios have been continuously monitored by using a quartz crystal microbalance. The morphology of the Pd/Ni systems has been studied by electron microscopy and shows a homogeneous deposition of granularly structured Pd onto the Ni substrate. X-ray diffraction analysis performed on Ni and NiO substrates revealed an amorphous structure, while the Pd coating crystallized into a fcc lattice with a preferential orientation along the [220]-direction. Surface chemistry analysis by X-ray photoelectron spectroscopy showed both metallic and oxide contributions for the Ni and Pd deposits. Cyclic voltammetry of the Pd/Ni nanocatalysts revealed that the electrooxidation of HCOOH proceeds through the direct dehydrogenation mechanism with the formation of active intermediates. High catalytic activities are measured for low masses of Pd coatings that were generated by a low number of ALD cycles, probably because of the cluster size effect, electronic interactions between Pd and Ni, or diffusion effects.

  7. Processes in Environmental Depositional Systems and Deformation in Sedimentary Basins: Goals for Exoloration in Mexico

    Science.gov (United States)

    Sandoval-Ochoa, J.

    2005-05-01

    Among the recent needs to establish new goals in the mexican energy industry to increase the petroleum reserves, has been necessary to recapitulate on some academic an operative concepts and definitions applied to the Petroliferous Basins Exploration; first of all, in order to understand the Petroleum System in given tectonophysical framework. The tectonophysical environment experienced by the petroliferous basin in the southwestern Gulf of Mexico, merely in the Campeche Sound and adjacent terrestrial regions (Figure 1); has been the result of interaction among the tectonic plates, the Coco's Plate with impingement and subduction beneath the Northamerican Plate and the Yucatán Microplate and even in very deep connection with the oceanic crust of southwesternmost portion of the Gulf of Mexico and the one of the Caribbean sea beneath the gulf of Belize-Honduras. The tectonosedimentary effects in the Campeche Bay starting with the skeleton formed for the Cenozoic Era, kept simultaneous conditions in depositions and deformations because of strain, stress and collapse fields, acted through this Era up to the present day, as observed in the surface Aguayo et al, 1999 and Sandoval, 2000. The involved portions of the crust and its boundaries have also been performing the relative sinking of the mere southwestern centre of the Gulf of Mexico, and the rising of the southeastern lands of Mexico. In the middle contiguity are found the productive Tertiary basins of: Comalcalco, Macuspana, Salina del Itsmo, Campeche-Champoton and other in deep waters; all of them, in an arrangement of basins among distensive faulted blocks in echelon, falling down to the deep centre of the Gulf Sandoval, op cit. With this scenario and that ones of other basins, a recapitulation on concepts and definitions, has been made on the regional natural processes of the environmental depositional systems and on the basins analysis in the tectonophysical framework, in order to reflect on the

  8. Equatorial Layered Deposits in Arabia Terra, Mars: Facies and Process Variability

    Science.gov (United States)

    Pondrelli, M.; Rossi, A.; van Gasselt, S.; Le Deit, L.; Glamoclija, M.; Cavalazzi, B.; Franchi, F.; Fueten, F.; Hauber, E.; Zegers, T.

    2012-12-01

    Genetic mechanisms proposed to explain Equatorial Layered Deposits (ELDs) formation include subglacial volcanism, aeolian/airfall, lacustrine, lacustrine/volcanic and spring-fed deposition. ELDs have been frequently shown to consist of sulfates (e.g. Gendrin et al., 2005) that might form as a response to evaporation in a playa environment (Hoefen et al., 2003) or during spring precipitation (e.g. Allen and Oehler, 2008; Rossi et al., 2008). The importance of groundwater-dominated hydrological systems was proposed to explain the formation of light-toned deposits in Meridiani Planum and Arabia Terra (e.g. Andrews-Hanna et al. 2007). Additionally, fluid expulsion processes have been invoked to explain the formation of mounds within the light-toned deposits in Arabia Terra (Allen and Oehler, 2008; Rossi et al., 2008; Pondrelli et al., 2011). Potential for habitable conditions of both playa and spring-related settings (Cavalazzi et al., 2007; Glamoclija et al., 2011) coupled with the high preservation potential within sulfates (Panieri et al., 2010), make these deposits a good candidate to understand the potential past habitability of the planet. In order to investigate ELDs genesis, an area in the vicinity of Firsoff crater, where ELDs are present within and outside the craters, was selected for geological mapping and analysis of the landforms and their association using the available dataset, including CRISM in order to infer ELDs composition. Within Firsoff crater, ELDs form a bulge that can be estimated to be at least a few hundred meters thick, while, outside the craters, ELDs form flat-lying deposits. Although heavily eroded by wind and carved by yardangs, several morphologies within the ELDs in the craters seem to be depositional, which would exclude that the entire Firsoff basin had been originally filled by ELDs. Within craters, ELDs consist of roughly meter thick layers draping and onlapping the substratum. They appear affected by polygonal patterns with no

  9. Electromagnetic sensors for monitoring of scour and deposition processes at bridges and offshore wind turbines

    Science.gov (United States)

    Michalis, Panagiotis; Tarantino, Alessandro; Judd, Martin

    2014-05-01

    Recent increases in precipitation have resulted in severe and frequent flooding incidents. This has put hydraulic structures at high risk of failure due to scour, with severe consequences to public safety and significant economic losses. Foundation scour is the leading cause of bridge failures and one of the main climate change impacts to highway and railway infrastructure. Scour action is also being considered as a major risk for offshore wind farm developments as it leads to excessive excavation of the surrounding seabed. Bed level conditions at underwater foundations are very difficult to evaluate, considering that scour holes are often re-filled by deposited loose material which is easily eroded during smaller scale events. An ability to gather information concerning the evolution of scouring will enable the validation of models derived from laboratory-based studies and the assessment of different engineering designs. Several efforts have focused on the development of instrumentation techniques to measure scour processes at foundations. However, they are not being used routinely due to numerous technical and cost issues; therefore, scour continues to be inspected visually. This research project presents a new sensing technique, designed to measure scour depth variation and sediment deposition around the foundations of bridges and offshore wind turbines, and to provide an early warning of an impending structural failure. The monitoring system consists of a probe with integrated electromagnetic sensors, designed to detect the change in the surrounding medium around the foundation structure. The probe is linked to a wireless network to enable remote data acquisition. A developed prototype and a commercial sensor were evaluated to quantify their capabilities to detect scour and sediment deposition processes. Finite element modelling was performed to define the optimum geometric characteristics of the prototype scour sensor based on models with various permittivity

  10. Nanostructured bioactive glass-ceramic coatings deposited by the liquid precursor plasma spraying process

    Science.gov (United States)

    Xiao, Yanfeng; Song, Lei; Liu, Xiaoguang; Huang, Yi; Huang, Tao; Wu, Yao; Chen, Jiyong; Wu, Fang

    2011-01-01

    Bioactive glass-ceramic coatings have great potential in dental and orthopedic medical implant applications, due to its excellent bioactivity, biocompatibility and osteoinductivity. However, most of the coating preparation techniques either produce only thin thickness coatings or require tedious preparation steps. In this study, a new attempt was made to deposit bioactive glass-ceramic coatings on titanium substrates by the liquid precursor plasma spraying (LPPS) process. Tetraethyl orthosilicate, triethyl phosphate, calcium nitrate and sodium nitrate solutions were mixed together to form a suspension after hydrolysis, and the liquid suspension was used as the feedstock for plasma spraying of P 2O 5-Na 2O-CaO-SiO 2 bioactive glass-ceramic coatings. The in vitro bioactivities of the as-deposited coatings were evaluated by soaking the samples in simulated body fluid (SBF) for 4 h, 1, 2, 4, 7, 14, and 21 days, respectively. The as-deposited coating and its microstructure evolution behavior under SBF soaking were systematically analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma (ICP), and Fourier transform infrared (FTIR) spectroscopy. The results showed that P 2O 5-Na 2O-CaO-SiO 2 bioactive glass-ceramic coatings with nanostructure had been successfully synthesized by the LPPS technique and the synthesized coatings showed quick formation of a nanostructured HCA layer after being soaked in SBF. Overall, our results indicate that the LPPS process is an effective and simple method to synthesize nanostructured bioactive glass-ceramic coatings with good in vitro bioactivity.

  11. Deposits on heat exchanging surfaces, causes in the bleaching process and countermeasures; Belaeggningar paa vaermevaexlare, orsaker i blekprocessen och aatgaerder

    Energy Technology Data Exchange (ETDEWEB)

    Bjurstroem, Henrik [AaF-Energi och Miljoe AB, Stockholm (Sweden); Staahl, Charlotte; Widell, Lars [AaF-Celpap AB, Stockholm (Sweden)

    2003-06-01

    Energy conservation in process industry implies to a large extent recovery of heat (or cold) from a process stream and its utilization for another process stream. The savings of energy that can be achieved depend on the process streams, but also on the efficiency of the heat exchange. A small driving temperature difference is a condition for an extensive recovery and a satisfactory preservation of its quality, i.e. its temperature. As process streams contain compounds or components that can precipitate and form deposits on heat exchanging surfaces, the recovery of heat is degraded. In the pulp and paper industry, two trends combine to increase the extent of fouling: a larger degree of closure for the process and a change in pH-profile caused by a switch to elementary chlorine free bleaching. In this study, the occurrence of deposits has been investigated for the mills that produce mechanical pulp and for the fiber line in mills producing chemical pulp. Deposits on the evaporator surfaces are treated in a parallel study. Except for some plants, deposits are not an important problem today. That does not mean that there has not been any problem or that problems will not occur. The origin of deposits lies in the chemistry of the process, but deposits have consequences for the thermal energy management. A list of possible actions in order to avoid deposits or to mitigate their consequences has been dressed in this report. They should be considered with the following order of priority: avoiding that the compounds that may form deposits enter at all the process, section 6.1; avoiding that these compounds form a deposit once they have entered the process, section 6.2; cleaning if nothing else helps or costs too much, section 6.3. Some of these methods are well known or are conventional changes in the processes. Some of these methods are less well proven or less well documented. In a longer time perspective, the kidney technology that is being developed could contribute to

  12. Spatial resolution in thin film deposition on silicon surfaces by combining silylation and UV/ozonolysis

    Science.gov (United States)

    Guo, Lei; Zaera, Francisco

    2014-12-01

    A simple procedure has been developed for the processing of silicon wafers in order to facilitate the spatially resolved growth of thin solid films on their surfaces. Specifically, a combination of silylation and UV/ozonolysis was tested as a way to control the concentration of the surface hydroxo groups required for subsequent atomic layer deposition (ALD) of metals or oxides. Water contact angle measurements were used to evaluate the hydrophilicity/hydrophobicity of the surface, a proxy for OH surface coverage, and to optimize the UV/ozonolysis treatment. Silylation with hexamethyldisilazane, trichloro(octadecyl)silane, or trimethylchlorosilane was found to be an efficient way to block the hydroxo sites and to passivate the underlying surface, and UV/O3 treatments were shown to effectively remove the silylation layer and to regain the surface reactivity. Both O3 and 185 nm UV radiation were determined necessary for the removal of the silylation layer, and additional 254 nm radiation was found to enhance the process. Attenuated total reflection-infrared absorption spectroscopy was employed to assess the success of